The future of cancer treatment: Whole genome sequencing?

The way we treat cancer is about to change: Genome sequencing may enable us to attack the very genes driving an individual's disease.
Written by Laura Shin, Contributor

We tend to think of everyone with, say, breast cancer as having the same disease.

Which, it turns out, isn't exactly accurate.

In reality, certain genes will drive one woman's breast cancer, while other genetic markers will drive another woman's disease. And, genetically, the cancer in one of these women may, in fact, have more in common with, say, lung cancer in another patient or even prostate cancer in a man.

Understanding the genetic drivers of cancer could pave the way for new treatments, reports The New York Times, and it has even shown very preliminary promise. Medical experts say that, someday, whole genome sequencing will lead to tailored cancer treatments that attack the specific genetic drivers behind a patient's cancer.

How genome sequencing could transform cancer treatment

Knowing the genetic makeup of the tumor will help doctors choose drugs to attack the problem genes and stop the cancer.

“Until you know what is driving a patient’s cancer, you really don’t have any chance of getting it right,” Dr. Dr. Timothy Ley, associate director of Washington University's genome institute, told The Times. “For the past 40 years, we have been sending generals into battle without a map of the battlefield. What we are doing now is building the map.”

The method is similar to current H.I.V. treatments, which use a multi-pronged drug therapy to attack the virus on several fronts.

But, for now, the method is in its infancy -- and it is complex. Once the genes are sequenced, the researchers have a billion small pieces. At that point, they must determine which mutations are the ones affecting the cancer.

Currently, the method is too expensive to be widely available -- the short list of people who have been able to try out the technology include Apple founder Steve Jobs, who paid $100,000 for it, and the writer Christopher Hitchens, who asked the head of the National Institutes of Health where he could get genetic analysis of his esophageal cancer.

But the cost of sequencing is dropping steeply, and research on genes is exploding, so medical experts believe that soon, whether it's a few years or a decade from now, genetic analyses of cancer will become routine. To get ahead of the curve, drug companies and small biotech firms are working on drugs that attack specific genes rather than types of tumors.

Similarly, cancer researchers are founding companies to track down genes that cause cancer to grow, and to find and test drugs against these genetic culprits. Venture capital firms are also getting into the field.

One promising tale

The Times's story centers around Dr. Lukas Wartman, a young leukemia researcher at the Washington University School of Medicine, who was diagnosed with the cancer he had devoted his life to studying.

With no other treatment available, his colleagues decided to sequence his entire genome, to see if they could find the gene that was driving his cancer, adult acute lymphoblastic leukemia. They fully sequenced the genes of his cancer cells, the genes of his healthy cells, and his RNA, which would also give hints as to what his genes were doing.

With the help of a supercomputer and one of the university's 26 gene sequencing machines, they spent a month of working frantically to beat the cancer clock.

The results showed that the cancer DNA had many mutations, but unfortunately, no drugs existed to attack any of them. However, the RNA results had one lead: One normal gene in the leukemia cells was in "overdrive, churning out huge amounts of a protein that appeared to be spurring the cancer’s growth," according to the Times.

Luckily, there was a new drug, Sutent, that could work on that malfunctioning gene. Though it had only been tested and approved for kidney cancer, the main obstacle to Dr. Wartman's receiving it was actually cost: It was $330 ... a day. His insurance company would not pay for it, despite two appeals, and Pfizer, the manufacturer, would not grant him a supply through its compassionate use program.

After scraping up some money to buy a week's worth, he began taking Sutent. His colleagues also pitched in to buy a month's supply for him.

"Two weeks later, his bone marrow, which had been full of leukemia cells, was clean, a biopsy showed," reports The Times.

Although he is now in remission, he has had some complications from bone-marrow transplants. Still, he is well enough to return to work -- in the same lab that pioneered his treatment.

His colleagues want to look for other leukemia patients who have the same mutation in their cancer cells, and start a clinical trial that tests Sutent on other leukemia patients.

(And they deserve a round of applause for their groundbreaking work, their devotion to healing Dr. Wartman, and their foresight in looking at whether this treatment could work on others!)

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via: The New York Times

photo: (MJ/TR/Flickr)

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