It’s even harder than we thought

Today, the New England Journal of Medicine publishes a paper that shows that genetic mutations—the garbled DNA code that can kill you—often differs within the same cancer tumor. This is a huge deal.

Why?

Because dozens, if not hundreds, of academic scientists and start up companies and big pharmaceutical firms are working furiously to develop anti-cancer treatments based on genetics: drugs that target genes that help tumors to survive and grow, or tests that can identify which particular kind of genetic chaos distinguishes your cancer, so that they can tailor your regimen to your cancer’s patterns.

Genetic testing is the reason doctors advised me to do chemo and radiation after surgery, even though my tumor was less than a centimeter in diameter: Apparently, my cancer’s genetics were nasty. The fact that doctors could parse this out has always made me feel a little safer. I was amazed when I first learned that my cancer had its own genetics, separate from my normal cells. Now, I’m not sure whether to feel safe or scared. What if my “tailored treatment” only zapped part of my cancer?

Cancer genetics is now oncology’s great white hope, just as chemotherapy was in the 1950s and 1960s, and radical surgeries were in the decades before that. About 15 of these genetic drugs are on the market now, hundreds more are in various stages of clinical trials. But these drugs don’t always work, and this new study may explain why.

Every time we think we’ve got a bead on cancer, we seem to find some new way that it’s even more complex than we thought. How could chaos—essentially, that’s what cancer is—not be complex? You can think of the war on cancer as a great battle between the forces of destructive chaos and the forces of genetic order. Maybe this is why cancer captures the public imagination in ways that Parkinson’s disease and diabetes do not. Luke Skywalker where are you?

A team of scientists in the United Kingdom took biopsies from four kidney cancer patients. They took these samples from different parts of the same tumors. Then they ran extensive genetic testing on the samples, far, far more than was done my tumor samples, or is done on any other patient’s. Cancer genetics tests normally cost $5,000 to $10,000. The scientists did tests that cost about 10 times that, analyzing the tumors in far more detail than is usual. And it cost precious time: sequencing one patient’s entire cancer genome took a very big computer four months.

After all that time and expense, the researchers found that not only is each person’s cancer different, but that one tumor can be multifarious. The same cancer gene can have different mutations within the main tumor mass, or they may differ between the primary sites and places where the cancer has metastasized.

While the study is very small, only four patients given the expense, the Associated Press reports that independent experts say they expect to find similar differences in breast, lung and colon cancers. The University of Texas MD Anderson Cancer Center has amassed a genetic database of 4,000 patients. They have found similar discrepancies in 40 percent of the database’s breast cancer patients.

This doesn’t mean that genetic tests or treatments for cancer are a dead end, only that they may not be the one magic key that unlocks cancer’s secrets. I suspect that we will never find that one key, because chaos just isn’t that orderly.