MELISSA BLOCK, HOST:
Now, some encouraging news about breast cancer. Scientists have pinpointed dozens of genetic mutations behind the four major types of the disease. Breast cancer kills nearly 40,000 American women each year. While researchers say no one should expect any overnight successes, these findings do give them many more ways to attack the disease with drugs. NPR's Richard Knox reports.
RICHARD KNOX, BYLINE: For at least a decade, experts have known breast cancer is really four different diseases. And that's helped improve treatment for some. But scientists haven't understood much about how these four types differ. The new report, published online by the journal Nature, is a big leap in that understanding.
MATTHEW MEYERSON: This paper gives us a level of detailed knowledge of breast cancer that vastly exceeds what was available before.
KNOX: That's Matthew Meyerson, one of the paper's 348 authors. He and his colleagues analyzed the genes from more than 800 breast cancer patients.
MEYERSON: We basically studied the genomes of the breast cancers from each of these women in comparison to the genomes of the rest of their bodies.
KNOX: They found 40 or so key differences in the genes among the four major types of breast cancer. All of these differences are potential targets for cleverly designed drugs. But Meyerson, who's with Dana Farber Cancer Institute in Boston, cautions it's a long way from the outmoded dream of coming up with a silver bullet that would knock out breast cancer or any other kind.
MEYERSON: I think in the end, to treat cancer we're going to be developing a lot of specific silver bullets, but we'll need to use them in combination. So you'll really need a gold bullet, and a silver bullet and a bronze bullet all together to effectively treat cancers.
CHARLES PEROU: And that arsenal is being developed, which is the good news, right?
KNOX: That's Charles Perou of the University of North Carolina, another study author.
PEROU: But the bad news is it's complicated. And we have to figure out, you know, which bullet to use, when and where, and that needs to be done in rigorous clinical trials and that is happening.
KNOX: But it's going to take a long time to find and test all those different bullets, says Karuna Jaggar of Breast Cancer Action, a consumer group.
KARUNA JAGGAR: For me, I have to say, my enthusiasm around this as new and exciting is somewhat dampened by the knowledge that it's going to many, many, many years before we see something that is clinically meaningful for patients. And in the meantime, too many women continue to be diagnosed with the disease.
KNOX: Fran Visco agrees.
FRAN VISCO: Finding targets, doing screening, genomic screening, that's not the end goal. That is simply a tool, a step in the way to figuring out how to save lives.
KNOX: She's president of the National Breast Cancer Coalition, another advocacy group.
VISCO: We have to be careful what we celebrate and we have to be careful what we consider to be success. We are nowhere near a success.
KNOX: Perou, the North Carolina researcher, understands their frustration.
PEROU: We're all, including myself, right, disappointed in the speed required to make these clinical advancements. It's far easier to make a discovery than it is to translate that discovery into a clinical impact.
KNOX: He thinks the first impact from this new research could be two to five years away. That would probably be for the most common type called luminal breast cancer. And that's because, the new paper shows, it has relatively few genetic mutations and there's already a drug in the works for one of them. Richard Knox, NPR News.
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