#WeCanICan #WorldCancerDay

A year ago tomorrow, I posted my first blog post. A year and nearly 100 posts later, I maintain the same mission I started with: to empower you with scientific knowledge so that you can make more informed decisions about your health.

February 4th is World Cancer Day, and they are running a social media campaign called “Talking Hands” so that people around the world can say how they take action to help prevent and fight cancer.  Besides what my biobanking team and the other clinical research teams are doing at St. Joseph’s Hospital and Barrow Neurological Institute to fight cancer, this blog is my personal contribution. I hope that in some way this helps you feel empowered to ask questions about yourself and your health, and in the case of a cancer diagnosis, feel better prepared to tackle your road ahead.

What can you do?

Photo Feb 02, 8 26 24 PM

Sci Snippet: Cancer vs. Tumor: What’s the difference?

It doesn’t matter to you what word you hear if you or a loved one is told by a doctor, “You have cancer” versus “You have a tumor.” Either way, there’s a wave of fear that is likely sustained through months, years, or a lifetime of treatment. It’s a diagnosis that nearly everyone has been touched by, so it’s something that everyone has talked about at one time or another.  The words tumor and cancer are typically used interchangeably, especially by people who are not in healthcare.  But it helps to know that there is an important distinction between cancer and a tumor when describing a mass of cells growing somewhere in the body.

The most important point is that a tumor DOES NOT mean cancer.  A tumor is a whole bunch of cells growing out of control (think of it as the cell turning on the gas pedal for cell division) creating a mass somewhere in the body.  Cancer, on the other hand, means that these cells have the potential to move and invade other parts of the body.A tumor can be benign (not cancer) or malignant (cancer).

Image of a benign meningioma. Thanks to Wikipedia for the image.

Image of a benign meningioma. Thanks to Wikipedia for the image.

What does it mean to be benign? A benign tumor still a huge mass of cells, and even though it may not spread to other parts of the body (the definition of malignancy and cancer), the mass could grow so large it presses against vital organs requiring surgical removal or causing death.  An example of a benign tumor is a meningioma.  This is a brain tumor that grows out of the covering of the brain and spinal cord, called the meninges, and although they do not typically spread to other places in the body (so they are not considered cancer), they do put pressure on the brain and spinal cord and usually have to be removed and may be treated with radiation.

benign_malignant

Thanks MedicineNet.com for the image

Cancer, on the other hand, is a tumor that has the potential to spread to other parts of the body, which is called malignancy.  This is one of the reasons that cancer is called cancer – from the Greek meaning crab because of the crab-leg like projections that are found in tumors that are invading neighboring tissue.  Tumors may be benign, malignant, or transition from something benign to something malignant.  For example, in the breast, masses of cells can form like papillomas that are a benign tumor that will not spread to other areas of the body. However, a breast cancer diagnosis implies that the breast tumor has the possibility to spread.  The only way to know whether a lump is a papilloma, breast cancer or something else is through a doctor and a biopsy.

It’s also important to note that not all cancers involve a tumor.  A great example of this are blood cancers that involve the increased growth of a particular type of blood cells, but will not have a tumor.

And in case you’re wondering where cysts fit into this, these are sacks filled with fluid, air or some semi-solid material. Cysts can be caused by a number of things including infection or clogging of glands. They may indicate a risk factor for a tumor or cancer, but are not cancerous themselves.

 

The difference between basic, translational and clinical research

When I started as a researcher, I had no idea that there were different types of research.  I don’t mean that some scientists study cancer and some scientists study Alzheimer’s disease.  I mean entirely different kinds of research that have fundamentally different methods, sources of funding, and purposes. Today’s post is going to outline three main types of research in the biological sciences: basic, translational and clinical research.

Basic Research:

science_image

By en:User:AllyUnion, User:Stannered (en:Image:Science-symbol2.png) [CC BY 3.0 or GFDL], via Wikimedia Commons

 Right off the bat, I need to be super clear that basic research is NOT research that’s easier to do or simpler than any other type of research.  It is just as complex and just as hypothesis-oriented as other types of research.  However, the goal of basic research is to  understand at a very basic level some aspect of biology.  Also called fundamental research, basic research doesn’t require that the outcome of the research can cure a disease or fix a problem.  That being said, basic research often does create the foundation that is required for other researchers to apply to solving a problem. I like how basic research is described on WIkipedia as “Basic research generates new ideas, principles, and theories, which may not be immediately utilized but nonetheless form the basis of progress and development in different fields”  This research can be in biology, physics, math, environmental sciences or any other scientific field. So what are some examples of basic research in biology?

  • Understanding the proteins and pathways that result in cells dying by apoptosis
  • Developing technology to better determine the 3D structure of proteins.
  • Creating mathematical models representing population growth in cities over time
  • Studying how leaf litter affects the ecosystem (an actual active funded grant at TGen here in Arizona)

This research is often funded by the government, specifically the National Institutes of Health, which funds 50,000 grants to more than 300,000 researchers at more than 2,500 institutions around the world, and the National Science Foundation, which funds 24% of all federally-funded basic science research in the United States.

Translational Research:

mouse_for_research

By Maggie Bartlett, NHGRI. [Public domain], via Wikimedia Commons

Translational research is how basic research and biological knowledge is translated into the clinic.  Often called “bench-to-bedside” or research (referring to the research bench and the patient’s bedside) or “applied” research (of applying basic research to solve a real-world problem), this research is needed to show that a drug or device works in some living system before it is used on humans. This is the research that happens after the results from basic research are obtained and before clinical research.

For example, if a drug is found in the lab that targets a protein that is thought to cause a disease like cancer, the drug will first be tested on animal models.  The animal model may be a mouse that has been genetically altered so that it develops that specific kind of cancer or a mouse that has human cancer cells injected into it (like the patient derived xenografts I described in a previous post). The drug will then be used on the animal to see if it is safe or if low doses are so toxic that the animal dies. Whether or not the drug hits the targeted protein or cell type can also be tested in mice.  For example, if the drug is supposed to kill brain tumor cells, researchers would want to make sure the drug was able to pass the blood brain barrier of the mouse.  Finally, if the drug is supposed to kill tumor cells, researchers would want to check that the tumor shrinks, the cells die, and/or that the survival of the mouse is extended from using this treatment. Often, drugs are “weeded out” at the translational research stage saving millions of dollars and years worth of time and effort in clinical trials.

Translational research isn’t just for drug development.  It is also useful for devices. For example, to develop a device that can diagnose diseases in third world countries, where access to electricity and high tech labs is more difficult.

Clinical Research:

blood_tube_for_research

By Tannim101 [CC BY 3.0, GFDL or CC BY 3.0], via Wikimedia Commons

Clinical research is what is performed in a healthcare environment to test the safety and effectiveness of drugs, diagnostic tests, and devices that could be used in the detection, treatment, prevention or tracking of a disease.  The cornerstone of clinical research is the clinical trial.  There are 4 basic phases to a clinical trial.  Each phase is performed sequentially to systematically study the drug or device.

  • Phase I: This is the first time the drug or device has been in humans and it is used on a small number of patients in low doses to see whether or not it is safe and what the side-effects may be. At this point, the clinicians are not trying to determine if the treatment works or not.
  • Phase II: In this phase, more patients are treated with the device or drug to test safety (because more side effects may be identified in a larger, more diverse population) and whether the drug or device is effective (in other words, does it work?).
  • Phase III: This is the phase that focuses on whether the drug or device is effective compared to what is typically already used to treat patients.  It’s used on a large group of people and “end points” like increase in survival or decrease in tumor size are used to evaluate its effectiveness.
  • Phase IV: These trials are done after the drug has gone to market to see if it works in various populations .

There are several different types of clinical trials depending on who is funding them. Some clinical trials can be initiated by a doctor or group of doctors.  These are call “physician-initiated” or “investigator -initiated”  studies and are often used to determine which type of treatment works better in patient care.  For example, there may be two treatments that are commonly used to treat a disease. Investigators may initiate a study to figure out what treatment works better in what patient population.

The kind of clinical research you may be more familiar with are drug companies who are working to develop a drug or device.  These companies will “sponsor” (aka “pay for”) a clinical trial.  They work with clinicians at one or more medical institutes to use their drug or device in a particular way (depending on the phase of the trial) and the clinicians report back the results, including whether there were any side effects to the treatment. At the end of the clinical trial, if the treatment or device was a success, the drug company can apply to the Food and Drug Administration (FDA) for approval to use the drug in the general population.  Bringing a drug to market is a timely and extremely expensive process estimated at over 10 years and $1.3 Billion dollars per drug. Much of this time and cost is due to high cost of conducting the clinical trials.

If you are interested in what clinical trials are currently available in the United States, all clinical trials are registered on ClinicalTrials.gov.  Anyone can search this database to see if trials are available for them to participate in.

Overall, each type of research needs to understand the other, and researchers need to work together to successfully understand our world and to come up with solutions to prevent, diagnose and cure disease.

The Cancer Genome Atlas Project (TCGA): Understanding Glioblastoma

TCGAIn 2003, Cold Spring Harbor Laboratory (CSHL) and researchers around the world celebrated the 50th Anniversary of the discovery of the structure of DNA by Jim Watson and Francis Crick.  I was a graduate student in the Watson School of Biological Science at CSHL, named after James Watson who was the chancellor of the CSHL, and in 2003, I participated in (and planned!) some of the 50th anniversary events. Coinciding with this celebration was a meeting about DNA that brought world-renowned scientists and Nobel Prize winners from around the world to CSHL to celebrate how much had been accomplished in 50 years (including sequencing the human genome) and to look to the future for what could be done next. That meeting was the first time I had heard about the Cancer Genome Atlas Project. At this point, the TCGA (as the project was affectionately called) was just a pipe dream – a proposal by the National Cancer Institute and the National Human Genome Research Institute (two institutes in the National Institutes of Health – the NIH).  The idea was to use DNA sequencing and other techniques to understand different types of cancer at the genome level. The goal was to see what changes are happening in these cancer cells that might be exploited to detect or treat these cancers.  I remember that there was a heated debate about whether or not this idea would work. I was actually firmly against it, but now with the luxury of hindsight, the scientific advances of the TCGA seem to be clearly worth the time and cost.

The first part of the TCGA started in 2006 as a pilot project to study glioblastoma multiforme, lung, and ovarian cancer. In 2009, the project was expanded, and in the end, the TCGA consortium studied over 33 cancer types (including 10 rare cancers).  All of the data that was made publically available so that any results could be used by any scientist to better understand these diseases. To accomplish this goal, the TCGA created a network of institutions to provide the tissue for over 11,000 tumor and normal samples (from biobanks including the one that I currently manage).  These samples were analyzed using techniques like Next Generation Sequencing and researchers used heavy-duty computing power to put all of the data together. So what did they find? This data has contributed to hundreds of publications, but the one I’m going to talk about today is the results from the analysis of the glioblastoma multiforme tumors.

Title: Comprehensive genomic characterization defines human glioblastoma genes and core pathways published in Nature in October 2008.

Authors: The Cancer Genome Atlas Network

gbmBackground: Glioblastoma is a fast-growing, high grade, malignant brain tumor​ that is the most common brain tumor found in adults.  The most common treatments are surgery​, radiation therapy​, and/or chemotherapy (temozolomide​). Researchers are also testing new treatments such as NovoTFF, but these have not yet been approved for regular use. However, even with these treatments the median survival for someone diagnosed with glioblastoma is only ~15 months.  At the time that this study was published, little was known about the genetic cause of glioblastoma – a small handful of mutations were known, but nothing comprehensive. Because of the poor prognosis and lack of understanding of this disease, the TGCA targeting it for a full molecular analysis.

Methods: The TCGA requested tissue samples from glioblastoma patients from biobanks around the country. They received 206 samples that were of good enough quality to use for these experiments.  143 of these also had matching blood samples.  Because the DNA changes in the tumor only happen in the tumor, the blood is a good source of normal, unchanged DNA to compare the tumor DNA to. To these samples, the study sites did a number of different analyses:

  • They looked at the number of copies of each piece of DNA. This is called DNA copy number, and copy number is often changed in tumor cells (see more about what changes in the number of chromosomes can do here)
  • They looked at gene expression.  The genes are what makes proteins, which do all of the stuff in your body.  If you have a mutation in a gene, it could change the protein so that it contributes to the development of cancer.
  • They also looked at DNA methylation.  Methylation is a mark that can be added to the DNA telling the cell to turn off that part of DNA.  If there is methylation on gene that normally stops a cell from growing like crazy, that methylation would turn that gene off and the cell could grow out of control.
  • In a subset of samples, they performed next generation sequencing to know the full sequence of the tumor genomes.

Results and Discussion: From all of this data, the researchers found  quite a bit.

  • Copy number results: There were many differences in copy number including deletions of genes important for slowing growth and duplications of genes the told the cell to grow more.
  • Gene expression results: Genes that are responsible for cell growth, like the gene EGFR, were expressed more in glioblastoma tumor cells.  This has proven to be an interesting result because there are drugs that inhibit EGFR.  These drugs are currently being tested in the clinic to see if this EGFR drug is a good treatment for patients with a glioblastoma that expresses a lot of EGFR.
  • Methylation results: They found a gene called MGMT that is responsible for fixing mutated DNA was highly methylated.  This mutation was actually beneficial to patients because it made them more sensitive to the most common chemotherapy, temozolomide.  However, this result also suggests that losing MGMT methylation may cause treatment resistance.
  • Sequencing results: From all of the sequencing they created over 97 million base pairs of data! They found mutations in over 200 human genes. From statistical analysis, seven genes had significant mutations including a gene called p53, which usually prevents damaged cells from growing, but when mutated the cell can more easily grow out of control
glioblastoma_pathways

This is the summary figure from this paper that shows the three main pathways changed in glioblastoma and the evidence they found to support these genes’ involvement. Each colored circle or rectangle represents a different gene. Blue means that the gene is deleted and red means that there is more of that gene in glioblastoma tumors.

Bringing all of this data together, scientists found three main pathways that lead to cancer in glioblastoma (see the image above for these pathways).  These pathways provide targets for treatment by targeting drugs to specific genes in these pathways. Scientists also identified a new glioblastoma subtype that has improved survival​. This is great for patients who find out that they have this subtype!  Changes in the methylation also show how patients could acquire resistance to chemotherapy. Although chemotherapy resistance is bad for the patient, understanding how it happens allows scientists to develop drugs to overcome the resistance based on these specific pathways.

Although this is where the story ended for this article, the TCGA data has been used for many more studies about glioblastoma.  For example, in 2010, TCGA data was used to identify four different subtypes of glioblastoma: Proneural, Neural, Classical, and Mesenchymal that have helped to tailor the type of treatments use for each group. For example proneural glioblastoma does not benefit from aggressive treatment, whereas other subtypes do. Other researchers are using the information about glioblastoma mutations to develop new treatments for the disease

To learn more about the Cancer Genome Atlas Project, check out this article “The Cancer Genome Atlas: an immeasurable source of knowledge” in the journal or watch this video about the clinical implications of the TCGA finding about glioblastoma

Personalized Medicine: A Cure for HIV

Personalized Medicine – finding the right treatment for the right patient at the right time – is quickly becoming a buzzword both in the medical field but also to the public. But is it just hype? No!  I discussed a number of examples of how personalized medicine is currently be used in breast cancer in a previous post. In this and future posts, I’ll talk about a few fascinating emerging examples of the promise of personalized medicine.  These are NOT currently being used for patient treatment as part of standard of care, but could be someday.

HIV

HIV lentivirus

The Human Immunodeficiency Virus (HIV), the cause of AIDS, is a virus that attacks the immune system.  This attack prevents immune cells from fighting other infections.  The result of this is that the patient is more likely to acquire other infections and cancers that ultimately kill them.  When first discovered in the early 1980s, HIV infection was a death sentence. Untreated, survival is 9 to 11 years.  In the past 30 years, antiviral treatments have been developed that, when taken as prescribed, essentially make HIV infection a chronic disease, extending life to 25-50 years. But there is no cure for HIV, and as of 2012, over 35.3 million people were infected with the virus.

The lack of a vaccine to prevent the disease or of a cure to treat those infected isn’t because no one is trying. Since the virus was identified as the cause of the disease, scientists have been working to find a prevention or cure (along with developing all of the antiretroviral drugs that delay/treat the disease). I’m not going to discuss all of this interesting research (though it is worthy of discussion), instead I’m going to talk about one patient, Timothy Ray Brown, who was cured of HIV/AIDS through a stroke of genetic understanding and luck!

Brown was HIV positive and had been on antiretroviral therapy for over 10 years when he was diagnosed with leukemia in 2007. His leukemia – Acute Myeloid Leukemia (AML) – is caused by too many white blood cells in the bone marrow, which interferes with the creation of red blood cells, platelets and normal white blood cells. Chemotherapy and radiation are used to treat AML by wiping out all of the cells in the bone marrow – both the cancer cells and the normal cells. Brown’s doctors then replaced the cells in the bone marrow with non-cancerous bone marrow cells of a donor.  This is called a stem cell transplant, and it is commonly used to treat leukemia – often resulting in long term remission or a cure of the disease.

But the really cool part of this story isn’t the treatment itself.  Rather it’s that that Brown’s doctor selected bone marrow from a donor that had a mutation in the gene CCR5. So what? The CCR5 protein is found on the outside of the cells that the HIV virus infects. CCR5 is REQUIRED for the virus to get inside the cell, replicate, and kill the cell. Without CCR5, HIV is harmless. There is a deletion mutation in CCR5 called delta32 that prevents HIV from binding to the cell and infecting it.  Blocking HIV from getting into the cell prevents HIV infection.  In fact, it’s been found that some people are naturally resistant to HIV infection because they have this deletion. Two copies of the gene are found in 1% of the Caucasian population, and it’s thought that this mutation was selected for because it also prevents smallpox infection.
HIV_ccr5So Brown’s doctors repopulated his bone marrow with cells that had the CCR5-delta32 mutation.  This didn’t just cure his leukemia but it also prevented the HIV from infecting his new blood cells, curing his HIV. He is still cured from HIV today!

What does this mean for others who are infected with HIV? Is a stem cell transplant going to work for everyone?  Unfortunately, no. This mutation is very rare, so finding donors with this mutation isn’t feasible.  Plus, this is a very expensive therapy that comes with risks such as graft-versus-host disease from the mismatch between the person receiving the transplant and the transplanted cells themselves. However, there are possible options to overcoming these challenges, including “gene editing.” In this method, T cells from HIV-positive patients would be removed from the body and then gene editing would be used to to make the CCR5-delta32 mutation in these cells.  These cells could then be re-introduced into the patient.  With the mutation, HIV won’t be able to infect these T cells, which would hopefully cure the disease, while avoiding some of the major graft-versus-host side effects. A small clinical trial tested this idea in 2014 (full article can be found in the New England Journal of Medicine), and HIV couldn’t be detected in one out of four patients who could be evaluated. Although this is a preliminary study using an older gene-editing technique, it shows promise for “personalized gene therapy” to potentially cure HIV.

Book Club: The Immortal Life of Henrietta Lacks

The_Immortal_Life_Henrietta_Lacks

Thanks to Wikipedia for the image

In 2002, one of my first set of experiments in graduate school was treating the prostate cancer cell line (named DU145) with a chemotherapeutic drug and comparing how these cells responded to how HeLa cells responded to this chemotherapy. Little did I realize at the time that 51 years earlier, these cells were removed from a poor black woman named Henrietta Lacks without her even knowing. She subsequently died, but her cells have lived on for over 60 years being used by researchers around the world to better understand cancer. It’s estimated that over 60,000 research papers have used HeLa cells (I just searched the literature for “HeLa” and found over 83,000 results). HeLa cells helped to develop the polio vaccine (HeLa cells were easily infected by polio, and therefore ideal to test the vaccine).  In 2013, HeLa cells were the first cell line to have its genome fully sequenced (the genome of HeLa cells is a hot mess with more than 5 copies of some chromosomes – likely caused by the number of times that the cells have divided over the past 60 years).  In fact, HeLa cells are so popular and so widespread that they have been found to be contaminating a large percentage of the OTHER cell lines that researchers are using (for example, the bladder cancer cell line KU7 was found to exclusively be HeLa cells in one research lab).

With all of this activity surrounding HeLa cells, you may think that she is famous and her family has received recognition from her donation.  However, as so artfully described in Rebecca Skloot’s “The Immortal Life of Henrietta Lacks” these cells were taken and grown without her consent and her family had no idea that Henrietta was was “immortal” through her cells growing in las around the world. Skloot describes the moral and ethical issues surrounding how these cells were obtained while weaving a story about Henrietta Lacks and her family’s life and discovery of HeLa cell’s fascinating rise to prominence.  Although the story is interesting to a scientist and a biobanker, the book is definitely written in such a way that the public will completely understand the scientific significance.

Growing tumors outside the body to kill the tumor still inside

To understand how to kill a tumor, you have to study the tumor. Historically, much of how scientists understand tumors comes from removing a tumor from a patient’s body, putting Cell_Cultureit in a plastic dish (called a petri dish), and studying whatever cells are grown in this dish. You may be familiar with the book “The Immortal Life of Henrietta Lacks” by Rebecca Skloot. This book talks about HeLa cells, which are cells that were taken from Henrietta’s cervical cancer, grown in a dish, and propagated for the past 60+ years as what is called a “cell line“.  These cells grow and divide indefinitely, and have been propagated and transferred from lab to lab to be studied.  HeLa cells are one of the most famous and most-researched cells that have helped scientists better understand cancer. HeLa cells are not the only cell line that exists or has been used to study cancer.  There are cell lines from lung cancer tumors, prostate cancer, brain cancer, and most other major cancers. However, there are a few problem with using cell lines to understand and treat cancer.

  1. Cell lines are EXTREMELY hard to create.  As you may imagine, a plastic dish is nothing like the environment inside the body that the tumor was removed from.  In the petri dish the cells are put into “media,”t he liquid that is used to feed the cells in the petri dish, and this media is also nothing like the nutrients and other growth factors feeding the tumor inside the body. Because of this unnatural environment, some of the tumor cells die – and in many cases mostor all of the tumor cells die.
  2. The cells that are left in the petri dish do not accurately represent the tumor anymore. A tumor isn’t a whole bunch of identical cells, but rather a tumor contains a lot of genetically different cells.  Scientists call this tumor heterogeneity. This is one of the reasons why drug resistant cells emerge after treating a tumor with drugs (like in the case of melanomadescribed in a previous post).  There are already drug resistant cells inside the tumor that don’t die when treated with drug.  Unfortunately, not all of these different cells in the tumor will live in a petri dish, so only a selected type or types of cells will live and can be studied.
  3. Even though cell lines had been the most useful tool in the past to understand cancer biology, they are not at all useful in understanding the EXACT tumor from a particular person. What does this mean? For example, drugs that kill HeLa cells in a petri dish might not work to kill another person’s cervical cancer because the genetic cause of that cervical cancer is different. In personalized medicine, the goal is to identify the drugs that will work to kill a particular patient’s tumor. Because of this, cell lines just aren’t good enough.

Scientists have been working on a number of solutions, and I’ll talk about four:

  1. Biobanking. A biobank collects excess tumor tissue from patients who are having a
    liquidnitrogenfreezers

    Where tumor tissue is stored in a biobank before researchers use it

    tumor removed as part of a surgery.  This tissue is immediately preserved by freezing and can then be used by researchers to study that particular tumor or many tumors of a particular type (e.g., lung cancer).  The disadvantage to this is that the tumor sample isn’t an unlimited resource. Once the tissue has been used up – it’s gone. The remaining examples all focus on growing the tumor tissue so that it can be propagated and used for many experiments.

  2. Modified cell line growth. HeLa cells were not grown in any special way, but researchers at Georgetown Universityhave found ways to grow tumor cells in a petri dish  that are identical to the tumor and nearly all tumors can grow under these conditions. So what are these conditions?  The researchers grow cells on top of a layer of mouse cells called feeder cells because they provide the cell-based nutrients to “feed” the tumor and allow it to grow.  They also use a particular inhibitor that allows the cells to grow indefinitely. They have created these modified cell lines from different types of tumors, from frozen biobanked tumors, and from as few as 4 live cells.  Even though this system, is better, it still doesn’t replicate the 3D architecture of a tumor…
  3. cancer organoids

    Cancer organoids. Notice the 3D clumps of cells after 217 days of growth. Thanks to the Kuo lab for the image

    Organoids. As you would expect the word to mean, an organoid is a mini 3D organ bud grown in a dish. Don’t imagine a teeny tiny beating heart.  These organoids are just clumps of cells, but an organized clump of cells that can help better understand cells and organs. The discovery of how to create organoids was so interesting that it was a 2013 Big Advance of the Year by The Scientists magazine. Scientist have also found a way to grow cancer cells into these 3D organoid structures. With tumor organoids, researchers can both study the genetics of the tumor (like you can with cell lines) as well as how the tumor behaved in a 3D environment that is more similar to what the tumor encounters in the body.  But what if we could do even better?

  4. Patient-derived xenograftsare when tumor tissue is taken directly from a patient’s tumor and put directly into a mouse.  Why would this be so awesome? The environment inside a mouse is more similar to the environment that the tumor is used to inside a person’s body.  The cells are less likely to die because they aren’t living in unnatural plastic. Also, a whole piece of tumor can be implanted into the mouse, maintaining the tumor cells connections to neighboring cells, which are critical for the tumor cells to communicate with one another for survival.

With all of these systems available to study tumors from a specific patient, what are scientists actually doing with these cells? In some cases, they are being used to sequence the genomes of the tumors to identify mutations that may be causing the tumor. If a tumor can be grown so that there is a lot of it, the tumor cells themselves can also be used to test treatments either in a dish or inside of a mouse. Imagine a cancer patient getting their tumor removed, part of the tumor is grown in one of the ways described above. Then the tumor is exposed to the top 10, or 50 or 100 anti-tumor drugs or combination of drugs to see what kills the tumor. This drug or combo of drugs can then be used to treat the patient. There are companies that are currently working on doing exactly this (check out Champions Oncology) so this “big dream” may soon become a cancer patient’s more promising reality.

 

The best week ever – Nobel Prize week!

nobelLast week was one of my favorite weeks of the year – Nobel Prize week. Some people wait for the Emmys or the Superbowl or Christmas.  I wait for the Nobels. To be fair, I care most about the science Nobels – Physics, Chemistry and Physiology or Medicine, though one cannot ignore the amazing accomplishments of the winners in Literature, Peace, and Economics. Every year, I try to guess who may win – though Thomson Reuters and others are far more scientific about their guesses than I am.  And each morning of Nobel Week, first thing I do is check the news on my phone to see who won, what for and whether or not I know them (this year – no).  Let’s talk about who won the science awards this year and what amazing discoveries they won for.

Physiology or Medicine. A lot of attention has been given to infectious diseases this year with the huge Ebola outbreak in western Africa.  Although tens of thousands of people were infected and died, other infectious diseases are even more widespread and affect millions of people a year. Malaria is a parasitic disease transmitted by mosquitoes that 3.4 billion people are at risk of contracting and that kills over 450,000 people per year. Parasitic worms are also rampant in the third world, can affect up to a third of the human population, and cause such diseases as river blindness.  This is the second most common cause of blindness by infection, with 17 million people infected and 0.8 million blinded by the disease.  The three winners of the Nobel for Physiology or Medicine this year discovered novel treatments for these parasitic diseases.  William C. Campbell and Satoshi Ōmura for roundworm parasites and Youyou Tu for malaria, saving hundreds of thousands of lives each year.

Chemistry. This is by far my favorite award this year because it is directly related to how humans safeguard their DNA, but also why when this safeguard does work, that we get cancer.  Awarded to Tomas Lindahl (UK), Paul Modrich (USA), and Aziz Sancar (USA), this Nobel celebrates the discovery of the mechanism of DNA repair. I’ve discussed in this blog how UV and other environmental factors can cause mutations in DNA, and with too many mutations, people can develop cancer or other diseases.  However, the genome doesn’t mutate out of control because cell contain the machinery that is always working to fix any DNA damage using DNA repair mechanisms. It’s like a NASCAR race, where the car is always being monitored, wheels replaced, and minor problems fixed by the pit crew.  DNA repair is the genome’s pit crew and these three scientists figured out three different ways that the cells monitors and fixes the DNA depending on the type of damage that has occurred.

Physics. We all know I’m not a physicist, but I’ll try my best. The Physics Nobel was awarded to Takaaki Kajita of Japan and Arthur B. McDonald of Canada for discovering that neutrinos have mass.  You may remember from high school that atoms are made up of protons, neutrons and electrons. However, scientists now know that there are even tinier parts of an atom called subatomic particles that include the neutrino, fermions and bosons (and others). Other than photons, which are the particles of light, neutrinos are the most numerous subatomic particle in the entire cosmos, so understanding how they work is incredibly important.  These researchers found that the three different types of neutrinos can convert from one to the other. It was predicted by the Standard Model of Physics that these neutrinos wouldn’t have mass, but these scientists also proved that they did. Their studies help to better understand matter and the universe. My favorite reporting of this award was by NPR.

So until next year Nobel Prizes.  I will be waiting with baited breath!

 

How scientists “cured” melanoma

When talking about Personalized Medicine, one of the recent shining examples of this concept in practice is in the treatment of melanoma. Melanoma is a cancer of the pigment cells called melanocytes and is most commonly diagnosed as a skin cancer. The prognosis for melanoma is dismal when caught at later stages where the cancer cells have spread into lower layer of the skin or throughout the body (see the stats in the image below). Treatment typically involves surgery to remove the cancer cells, followed by chemotherapy and/or radiation therapy, but the response to these treatments is low.

melanoma

There are two interesting personalized medicine examples for melanoma.  The first is in determining whether a low stage (I or II) melanoma has a likelihood of spreading.  Once a low stage melanoma has been removed by surgery, there is still a 14% chance that these patients will develop metastatic (melanoma that spreads) disease. To determine which patients are more at risk, a biotech company developed DecisionDx-Melanoma. This test looks at the expression of 31 genes and separates the patients into two groups based on the gene expression profiles.  One group only has a 3% risk of developing invasive melanoma within 5 years whereas the other group has a 69% chance.

However, whether the cancer progresses or not, treatment is still an issue. That is, it was until a few years ago when scientists found that  50-60% of all melanoma patients have a mutation in the gene called “BRAF.” This mutation tells the cancer cells to grow faster, so you can imagine that if you stop this signal telling the cancer cells to GROW, then they might stop growing and die. This is exactly what the drug PLX4032 (vemurafenib) does – it inhibits this mutated BRAF and stops the cancer cells from growing in 81% of the patients with this mutation (see the photo at the bottom of the post to see how dramatic this effect is).  On the other hand, in patients without this mutation, the drug has severe adverse effects and shouldn’t be used.  Because of this, doctors don’t want to prescribe this treatment to patients without the mutation.  Therefore, scientists created a companion diagnostic.  These are tests that are used to identify specific mutations before treatment to help decide what treatment to give (see image below). In the case of melanoma, this companion diagnostic tests if the patient has the BRAF mutation, and the patient is only treated with vemurafenib if they have this mutation.

This treatment was revolutionary with an incredible ability to cure melanoma. It was like melanoma was previously being treated with the destruction of a nuclear bomb, and now it is being treated with the precision of a sniper rifle – targeting the exact source of the cancer. So why is the word “cure” so obviously in quotes? Unfortunately, after continued therapy, the cancer relapses (see the image below). Imagine treating cancer cells being like closing a road- it’ll block up traffic (kill the cancer cells), but then you’ll be able to find back roads that get you to the same place.  In the case of cancer, the drug is targeting mutations in BRAF, and BRAF finds ways to evade the drug by mutating again (effectively removing the roadblock).  Or the cancer cells themselves may have other routes besides mutated BRAF making the cancer grow. So although this drug is a life extender, scientists have been working to combine it with other targeted drugs (blocking off alternative routes) to make it a long-term life saver.

melanoma_relapse

From the Journal of Clinical Oncology

What is Personalized Medicine?

bullseyeA few years ago I was asked to teach a course to adults at the ASU Osher School of Lifelong Learning about the Emerging Era of Personalized Medicine. This was exciting because it would give me the opportunity to help empower these adults to better understand their health, the science behind what make them sick, and what scientists and doctors are doing to cure them.  This was also a challenging course to develop because only a few years ago personalized medicine wasn’t the common buzzword like it is today. In fact, in early 2014, the Personalized Medicine Coalition contracted a research survey that found that 6 in 10 of people surveyed hadn’t heard of the term “personalized medicine” (see all results of the survey here). Despite the public being unaware of this huge advance, in the past few years, scientists and doctors continue to evolve this concept and medicine isn’t just “personalized” but now it can also be described as “precision,” predictive,” “individualized,” “stratified,” “evidence-based,” “genomic” and much, much more.

So what is new about this type of medicine?  Of course since the days of Hippocrates, doctors have provided care to patients that take their “personalized” needs in mind. Based on the patient’s symptoms and their experiences, the doctor provides treatment. But what if two patients have the same symptoms but different underlying diseases?  A fever and a headache could be the flu or malaria. Or two people could have the same disease, like breast cancer, but the underlying genetic changes are different so that the cancer should be treated differently for each patient.

The current concept of personalized/precision medicine uses each person’s individual traits (genetic, proteomic, metabolomic, all the -omics) and harnesses our molecular understanding of disease for the prevention, diagnosis, and treatment of disease.

personalized-med2The ultimate goal of personalized medicine is to improve patient health and disease outcomes. The graph above shows how better understanding the genetic and molecular causes of disease can improve health at all phases of disease progression.

  1. Knowing the risk factors that cause of disease (either environmental, like smoking, or genetic, like the BRCA gene mutation) can help to prevent disease before it starts by eliminating the risk factors or providing additional screening to catch the disease early.
  2. Biomarkers that detect disease before major symptoms can be used to treat the disease early, which usually has a better outcome than treating a disease that has progressed further (think stage 1 versus stage 4 metastatic cancer).
  3. Once a disease has been diagnosed, the molecular understanding of the disease can help determine what treatment the patient should receive (see below for an example).
  4. Biomarkers can also be used to predict whether the disease will progress slowly or quickly or whether or not a selected treatment is working.

For all aspects of personalized medicine, there lies the promise to make an enormous impact both on public health but also on decreasing the cost of healthcare.

breast_cancerLet’s use breast cancer as an example of how personalized medicine plays out in real life, right now. For breast cancer detection, breast self-exams and mammograms are typically used.  With personalized medicine, we now have an understanding of one of the genetic risk factors of breast cancer – mutations in the BRCA genes.  Patients at higher risk for developing breast cancer because of these mutations can be monitored more closely or preventative action can be taken. In the past, breast cancer treatment focused on treated with non-specific chemotherapy and surgery. Although both of these treatments are still of value, now doctors also test for the presence of certain breast cancer genes like Her2.  If Her2 is present in breast cancer cell, the drug Herceptin that specifically targets this Her2 gene can be used to specifically kill those cancer cells. If Her2 isn’t present, this drug isn’t effective, causes negative side effects and wastes time and money when a more effective treatment could be used.  Once breast cancer is diagnosed, a patient would be interested in knowing how quickly their cancer will progress. This used to be primarily based on the stage of the cancer, where stage 4 cancers have spread to other locations in the body so the prognosis isn’t great. Based on molecular markers, scientists have now created panels of biomarkers (Oncotype DX and MammaPrint) that predict breast cancer recurrence after treatment.

These personalized medicine-based tests and drugs are incredible. However, this is a field that both holds considerable promise and requires lots of work to be done.  For every incredible targeted therapy developed, there are patients that are still waiting for the treatment for their disease or the genetic variant of their disease.  In future posts, I’ll talk a lot about both the promise and the pitfalls of personalized medicine.

If you want to learn more about personalized medicine, check out this YouTube video with a cartoon comparing treatment with and without the concept of personalized medicine.