Genetic ‘Signature’ in Breast Cancer Tumors May Predict Disease Progression, Chance of Survival

Researchers have detected a "genetic signature" in breast tumors that appears to be a "powerful predictor" of whether the cancer will metastasize and be fatal or whether the cancer can be cured "easily" with surgery, the New York Times reports (Kolata, New York Times, 12/19). The study, conducted by researchers at the Netherlands Cancer Institute and published today in the New England Journal of Medicine, identified a series of 70 genes that can predict the severity and potential fatality of breast cancer with a "high degree of accuracy," the Boston Herald reports (Lasalandra, Boston Herald, 12/19). Researchers compared tumor samples from 295 women ages 52 or younger treated at the Netherlands Cancer Institute, matched the data with the patients' medical records and used the 70-gene "fingerprint," which was previously taken from "tens of thousands" of tumor-gene signals by pattern-matching software. Researchers determined that patients identified as having a "good prognosis" through the fingerprinting had an 85% chance of surviving 10 years without metastasis, compared to only a 51% chance for the group identified through the fingerprinting having a "poor prognosis" (Hamilton, Wall Street Journal, 12/19). The genetic signature seems to "predict cancer mortality" better than does tumor size or the stage in which the cancer was detected, the Times reports. The finding also appears to "challeng[e] some long-held beliefs," including that smaller tumors are more treatable. Based on the findings, tumors are either potentially deadly or not from the beginning, regardless of size (New York Times, 12/19).

"What this is all telling us is the fantastic promise of this field," Dr. Carlos Caldas, a cancer specialist at the University of Cambridge, said, adding, "I think it's going to completely change the way we practice" (Donn, AP/Philadelphia Inquirer, 12/19). Janet Skidmore, a spokesperson for Merck, whose subsidiary Rosetta Inpharmatics worked with researchers on the study, said the technique will be available to physicians and patients "within a few years." However, researchers cautioned that more studies are necessary to confirm the findings, the Newark Star-Ledger reports (MacPherson, Newark Star-Ledger, 12/19). CBS' "Evening News" yesterday reported on the genetic fingerprinting (Kaledin, "CBS Evening News," CBS, 12/18). A transcript of the segment and a video excerpt in RealPlayer are available online.