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What is personalized medicine?

Would your teenaged son buy the same clothes as his grandmother? Probably not. But when theyget sick, theyre likely receive just about the same treatment and drug choices. Andso willeveryone else. Thats because even the worlds best scientists and doctors have limited

knowledge of how different people respond to different treatments. The result is a "one size fitsall" approach to medicine.

Thats changing. Personalized medicine is moving us closer to more precise, predictable, andpowerful medicinecustomized for the individual patient. Our growing understanding ofgenetics is allowing us to provide better diagnoses, safer drug prescribing, and more effectivetreatment of the diseases and conditions that have affected us throughout history.

Today, scientists and doctors are learning how to tailor health care to a persons unique genetic

makeup. Thats the idea behind personalized medicine.

The benefits of personalized medicine

Throughout history, the practice of medicine has largely been reactive. Even today, we have to wait until

the onset of diseases and then try to treat or cure them. And because we dont fully understand the

genetic and environmental factors that cause major diseases such as cancer, Alzheimers and diabetes,

our efforts to treat them are often imprecise, unpredictable and ineffective.

In addition, the drugs and treatments we devise are tested on broad populations and are prescribed

using statistical averages. For example, on average, any given prescription drug now on the market only

works for half of those who take it. Among cancer patients, the rate of ineffectiveness jumps to 75

percent. Anti-depressants are effective in only 62 percent of those who take them.

Personalized medicine is beginning to transform the practice of medicine. It is allowing health care

providers to:

Shift the emphasis in medicine from reaction to prevention

Predict susceptibility to disease, improve disease detection, preempt disease progression

Customize disease-prevention strategies

Prescribe more effective drugs and avoid prescribing drugs with predictable side effects

Reduce the time, cost, and failure rate of pharmaceutical clinical trials, and

Eliminate trial-and-error inefficiencies that inflate health care costs and undermine patient care

Personalized medicine means that one day, doctors and genetic counselors will be able to craft a lifelong

health maintenance strategy tailored to a persons unique genetic constitution. It will be possible to

predict susceptibility to diseases and to prevent, delay or mitigate those diseases with precisely chosen

medicines, therapies and customized lifestyle advice.

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Current applications of personalized medicine

While it may be decades before we see the full benefits of personalized medicine, initial benefitsare already here. For example, genetic analysis of patients dealing with blood clots, colorectalcancer, and breast cancer are driving treatment advantages that, until recently, were impossible:

Blood clots. Before the availability of genome-based molecular screening, the dosing ofWarfarin, which is prescribed 21 million times a year, was a dangerous game in which too littleof the drug could trigger more clots and too much could lead to excessive bleeding.

Since 2007, the U.S. Food and Drug Administration has recommended genotyping for allpatients being assessed for therapy involving Warfarin. Genotyping allows prescription of drugtherapy regimens only to individuals expected to benefit from that specific drug at that specificdosage.

Colorectal cancer.Metastatic colorectal cancer kills 50,000 Americans every year, more lives

than are lost to breast cancer and AIDS combined. Among the drugs most frequently used intreating colon cancer is cetuximab (sold as Erbitux by Bristol-Myers Squibb).

For colon cancer patients, the biomarker that predicts how a tumor will respond to certain drugsis a protein encoded by the KRAS gene, which can be now be determined through a simple test.Because cetuximab is effective only in colon cancer patients with normal KRAS protein,treatment with the drug can be withheld from the 40 percent of patients for whom it would proveineffective. Alternative therapies can be pursued immediately instead.

Breast Cancer.Just as molecular diagnostic testing of tumors determines which colon cancerpatients are most likely to benefit from drug therapy using cetuximab, women with breast tumors

can be screened to determine which receptors, if any, their tumor cells contain.

For example, the cells of the highly aggressive "triple-negative" breast cancer have no estrogen,progesterone, or human epidermal growth factor receptors, which are essential to the efficacy ofcurrent anti-breast cancer therapies. The application of personalized medicine eliminates both theconsiderable expense and precious time of trial-and-error treatments and helps clinicians todetermine quickly which breast cancer therapies are most likely to succeed.

The societal impact of personalized medicine

Along with many potential benefits, personalized medicine brings with it legal and ethicalquestions that we must answer as a society:

Who should have access to a persons genetic profile? Employers? The government? Lifeinsurance companies? Health insurers?

How will we protect genetic privacy and prevent genetic discrimination in the workplaceand in our health care?

And how will we as consumers use genetic information to our benefit?

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Questions like these loom large as the genomic revolution accelerates. Lawmakers, scientists andhealth advocacy groups have spent more than a decade urging federal legislation to preventgenetic discrimination. In 2008 Congress overwhelmingly approved the Genetic InformationNondiscrimination Act (GINA), and President Bush signed it into law. Many states haveadditional laws in place.

The Jackson Laboratory is committed to giving policy makers, legislators, ethicists, educatorsand consumers the information they need to address the ramifications of personalized medicineand to protect against genetic discrimination in matters of health insurance and employment.

Related technology

Less than a decade ago, the Human Genome Project gave us the complete sequence of the humangenome. It cost about $3 billion and took more than ten years to complete. Today, research andtechnology are driving the progress needed to make personalized medicine accessible to all.

Scientists can now sequence a human genome in about a week, at a cost of $10,000. As both thecost and time involved continue to plunge, it may soon be possible to sequence genomes in hoursfor $1,000.

Faster, cheaper DNA sequencing allows scientists to hunt for the genetic variations responsiblefor many diseases and conditions. Whole-genome analysis will provide doctors with more andmore ways to apply personalized medicine in the clinic. Through its contributions to the MouseGenome Informatics (MGI) database and other essential global resources, The JacksonLaboratory plays a critical role in using technology to realize the promise of personalizedmedicine.