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The American Cancer Society

The Future is Now: Personalized Medicine

April 18, 2012

By James C. Salwitz, MD


What does personal medicine mean to you?  A doctor who greets with your name and a smile?  Caregivers who listen? Physicians who know all about your case and every treatment you have received? We all want doctors who truly understand us.  In the near future, this personal understanding will go deeper than ever before.

 

The instructions for life lie in our chromosomes.  Everything about the way our bodies are built is coded in our DNA.  Every cell, muscle, nerve, and organ is constructed from genetic blueprints. Tall or short, brown eyes or blue, man or woman, it is all in our genes. Genes define much of who we are and what makes us different.  We now understand that genes have a lot to say about the diseases from which we suffer.

 

Some genes make us resistant to illness. We all know families where everyone lives into their 90s. Other genes increase the risk of specific disease.  How often have we met siblings with the same illness? DNA codes how our bodies fight disease or heal from injury.  Hard wired in our chromosomes are instructions to make drugs work, fail, or produce side effects.  The human genetic code is often the key to health and to disease.

 

Cancer is a result of damage to our genes.  Cancer occurs when the switches inside your genes that control cell growth malfunction.  If a growth gene is supposed to be turned off, it turns on.  If a genetic switch is designed to prevent cancer growth, it fails. Cells that should be at rest begin to divide, and a tumor develops.

 

 

These damaged growth genes are called oncogenesThe damage can occur for three reasons.  First, we may be born with a defective gene, such as the BRCA breast cancer gene. Second, exposure to toxins in our environment, such as smoking, can damage our genes.  Finally, the genes simply wear out, which partially accounts for the increase in cancer as we age.

 

Knowing that oncogenes are the key, there can be no doubt that genetic based prevention and therapy will be crucial to winning the war on cancer.

 

The future: medicine based on our genes

 

Personalized medicine will be medical care based on our very core.  Medicine based on our genes. This will completely change how treatments are given.  Today, your physician picks therapies based on research done on thousands of other people.  Doctors have only a limited ability to adjust therapy based on individual differences.

 

Researchers are working toward a future where each of us will have the opportunity to get a blood test to have a complete analysis of the 20,000 coding-genes which is our personal genetic blueprint. This data will be stored in our personal electronic medical chart. It will tell your physician critical information. What diseases are you likely to get? Heart disease? Colon cancer? Arthritis? Alzheimer's? What should be done to help prevent those diseases? Exercise? Yearly colonoscopy?  Drugs? Gene therapy? What treatments will work for you, as an individual, and which will harm you? 

 

In the future, if you do get cancer, the tumor itself will be tested. What oncogenes are turned on? What genes are turned off? What caused this to happen? Most important, what needs to be done to turn off those cancer genes and destroy the disease?

 

Science fiction? Not at all. We are starting to see the first use of personalized medicine techniques now with cancer treatment. Eventually, we will see this type of therapy for all human illness.

 

Breakthroughs are occurring

Many of the first breakthroughs in personalized medicine have occurred in breast cancer research.  The identification of genes linked to breast cancer (BRCA1, BRCA2, CDH1, CHEK2, PTEN, p53, ATM) allows us to warn women and men at increased risk for cancer decades before it might develop. Individuals can then make decisions to help prevent or detect cancer early. 

 

For women diagnosed with breast cancer, genetic testing on the cancer itself can help determine the need for chemotherapy and whether it will work (Oncotype-Dx).  Finally, we are using drugs that directly attack targets in breast cancer cells detected by genetic testing (HER2).

 

Chronic myelogenous leukemia (CML) is a blood cancer.  This leukemia is caused by a specific genetic injury called BCR-ABL, also known as the Philadelphia Chromosome.  Multiple medications have been created which specifically attack this gene (imatinib, dasatinib, nilotinib).  Remarkably, these treatments can be taken by mouth, have few side effects, and in some patients, may actually cure them.

 

Lung cancer is a menace. Scientists have identified dozens of oncogenes that stimulate its growth. For example, we know that if certain genes are mutated, this leads to rapid lung cancer growth. With information about which oncogene is causing the cancer to grow, specific therapies can be developed to block that gene.  The drug erlotinib only works if one type of gene is damaged. The medication crizotinib kills lung cancer by blocking another mutated gene. These treatments, which target specific genes, are resulting in some of the best response rates ever seen in lung cancer. Researchers believe future cancer therapy will consist of drug mixtures to block all activated oncogenes.

 

Cetuximab and panitumumab are two antibodies that were developed to treat colon cancer. However, at first it seemed as if they were a failure because they did not work in many patients. Then, it was discovered that if a cancer cell has a specific genetic mutation, known as K-ras, these drugs do not work.  This is an excellent example of using individual tumor genetics to predict whether or not treatment will work.  In the past, the oncologist would have had to try each therapy on every patient and then change when the cancer continued to grow.

 

A remarkable drug recently came on the market for a disease in which there is often little hope. Metastatic melanoma patients using vemurafenib are outliving patients who do not take the drug.  This drug came out of research showing that a key genetic injury in melanoma is the BRAF mutation. Scientists then designed a medicine to attack that mutation.

 

Last year, more than 40,000 articles were published on cancer care. The most exciting of these related to personalized medicine. Genetic discoveries in brain tumors, pancreatic tumors, liver cancer, kidney cancer, leukemias, myelodyplasia, sarcomas, and oral cancers fill the medical journals.  New techniques are being developed to study parts or even the entire genome.

 

Healthy living makes a difference

 

Our increased understanding of the genetic basis of disease has helped us realize how important it is that we take good care of our bodies. Smoking, obesity, and alcohol kill by causing DNA damage or exploiting genetic weakness.  Exercise and a healthy diet are vital. Genomics will determine how these lifestyle decisions help cause or prevent disease. Personalized medicine will help each of us design lives to decrease the risk of illness and fight it when it occurs.

 

When Watson and Crick discovered 60 years ago that our bodies were coded in genes, it was an accomplishment with deep and lasting impact. Science has now connected genes and disease.  Physicians will use that knowledge to fight illness.  Soon, the most personalized statement of medicine will be, "you are cured."


Dr. Salwitz is a practicing medical oncologist in New Jersey and a past president of the Middlesex County chapter of the American Cancer Society.

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Comments

4/21/2012 12:57:55 AM #

Dr Pullen

All of this is exciting and promising, but the benefits so far have been elusive.  My wife has a BRCA2 mutation, and as such has been eligible for two new and exciting studies, both of which have failed to be as effective as hoped.  Living with cancer remains a fact of life for many patients, and is a challenge in itself.

We all remain hopeful that the improved DNA based research will lead to breakthroughs in choosing individualized therapy, but so far the reality is that it is sometime in the future for most patients.

Dr Pullen

4/22/2012 12:02:19 PM #

mexican

funny thing DRs. MD and other people involved in the posting of this website either left out very important details or are involved with the suppressing information that the minority of us all now know is that, common medicine sold to us in the pharmacys and prescribed by doctors have a risk of cause DNA' damage as well as stateing "risk of Cancer" listen to the commercials people??

the fact is many other risk in your enviroment causes immune suppression and damage..
for one all "Cooked Food" we know this is not genetic but in fact a carcenogen.  forget cigarettes you all need to be
worried more about the enviroment from your water and microwaves, pesticides and anything your putting on your body
is being absorbed through your largest organ which is your skin?? if man makes it or process it in a factory then 9 times
out of 10 the structure of that food has been altered in some way.  Eat Natural and Research outside medicines im not attacking the pharmacies but cancer is more than from tabacco and genetics, thats misleading because actually we are treating the symptom of poor nutrition with medicine and the same carcenogenic diets as with the start of the problem in mankind.  infact dr.s dont have any knowledge about nutrition and how to eat healthy they too have this free radicals growing inside them everyday..   start eliminating toxic foods from your diet every week and document them so that you can learn about them and teach others..

research : "Akaline foods" and "Acidic foods" this would be my start even for the doctors?
research: "flouride effects" Plastic goods, chloride, artificial sugars, processed foods.
good health and good life..

thank god for dr.s and other healthcare but we have to get healthy so someday these companies will make more money creating a cure for disease rather than treating the symptoms.

my 2 cents.

mexican

4/23/2012 9:46:01 PM #

James Salwitz

Dr. Pullen is of course correct... Personalized Medicine is a promise of future cures, but for now many people continue to suffer.  The daily battle against this terrible disease continues.

"mexican"'s basic comments are equally valid.  There is no doubt that most cancer comes from our environment and the damage it does to cancer causing genes.  There is much more to be learned about how we can protect ourselves and live healthy lives.  

jcs

James Salwitz

4/25/2012 6:12:58 PM #

Bradley Crandall

I have recentley been going through treatment for stage 2 hodgkins lymphoma, isolated to the left groin area.  The Oncologist treating me said it would a 4 course chemo then, depending on results, radiation therapy or 2 more courses of chemo. I have completed 3 treatments of chemo and to his surprise all signs of swelling, as well as, known symptoms have been irradicated. But, when I ask for a PET scan he is insisting on the treatment plan as prescribed by the book. To have a treatment plan based off of my unique genes would be a blessing to me.
I have a strong immune system that has kept me from truly being sick throughout my life time. If  I need more chemo so be it, but if another form of treatment would be less invasive on my body I would still get the job done then this is the treatment I would rather be offered.

Open-minded Opinion

Bradley Crandall

4/26/2012 12:52:03 PM #

Jim Salwitz

One of the reasons the cure rate is so high for Hodgkin's DIsease is that there has been extensive research over almost 50 years in treatment design.  The testing and treatment course you are describing seems to fit the internationally recommended and supported guidelines.  While there may be individual issues with a specific patient which are best reviewed with the treating oncologist, most patients are cured because of carefully designed and research supported therapeutic guidelines.  It is when we stray from those guidelines, that patients get in trouble.

To date it sounds, without having access to further details about your case, that you are doing very well.  While you should definitely discuss your concerns with your oncologist, and if you are unsatisfied get a second opinion, I would recommend you hang in there and complete the recommended therapy.

jcs

Jim Salwitz

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