For optimal cancer therapy, it would be important to know which genes in cancer cells have altered in the patients. In the largest cancer genome study of its kind now, American doctors have sequenced the genomes of tumors from 50 breast cancer patients and compared with the DNA sequences of healthy cells of the same patient.
Surprisingly, the researchers found only a few mutations that occurred with greater frequency. Instead, the varied nature of the mutations between the patients very much. Regardless, the pending analysis of DNA sequences provide important information for better, individual therapy, the scientists said at the annual meeting of the American Association for Cancer Research in Orlando. “Cancer genomes are extremely complicated. This explains the difficulty to predict the treatment outcome and to develop new treatments,” says Matthew Ellis of Washington University in St. Louis, one of the leaders of the project.
Overall, the researchers found more than 1700 mutations. However, most of which came to only one patient. In addition to two known mutations that are present in 40 or 20 percent of cases, researchers identified only three other, previously unknown mutations that were detectable at least ten percent of the tumors. And 21 more altered genes occurred in only two to three patients.
All tumors in the study were estrogen receptor-positive, meaning their growth was strongly stimulated by estrogen. Nevertheless, only in half of cases, effective cancer drug that blocked the estrogen effect. It is not known why the anti-hormonal therapy is effective in some estrogen receptor-positive cancers, and not for others. Detailed analysis of sequence data now available to help you find the cause.
The cancer genome research is an important step towards personalized medicine. It is routinely the tumor genome of the patients are sequenced in the not too distant future after a cancer diagnosis, so that a possible to this type of cancer tailored, optimal therapy.