Researchers at Harvard-affiliate Dana-Farber Cancer Institute have identified a group of genes that may predict whether certain breast tumors will recur after being treated by the most common chemotherapy drugs.

The study, led by Andrea L. Richardson, a professor of pathology at Harvard Medical School and Zhigang C. Wang, a professor of surgery at the Medical School, discovered two genes located on a chromosome whose presence amplified resistance to anthracycline drugs. The pair of genes, found in 20 percent of the samples, inhibits cancerous cell death and prevents the chemotherapy drugs from reaching the cell nucleus.

According to Richardson, this preliminary research may ultimately provide an alternate approach to treatment for breast cancer patients.

“Our findings suggest that you can do a test for the expression of these two genes and predict which tumor will be resistant to anthracyclines,” she said. “Because it is one of the most commonly used agents in treatment, it would allow us to tailor which kinds of therapy will be the most effective for our patients.”

Medical School Professor Craig A. Bunnell, who works in Dana Farber’s Breast Oncology Center, said women diagnosed with early-stage breast cancer often have tumors surgically removed before the disease can metastasize. Following surgery, patients receive chemotherapy to destroy any microscopic cancerous cells traveling through the bloodstream and may also undergo hormone and radiation therapy. The dilemma, Bunnell said, is determining which patients will benefit from chemotherapy. Though many stay in remission after chemotherapy, others relapse.

“All of the decisions that we as doctors must make are calculated by analyzing the risks over the benefits,” Bunnell said. “We don’t want to subject a patient to the side effects and the toxicities associated with chemotherapy if she will not derive benefits from the drug.”

Karen S. Anderson, an oncologist at Dana Farber, said that this preliminary research may also stimulate other investigations about the nature and the development of cancerous cells.

“These genomic-based studies are important because they may help us identify biomarkings that will allow us to tailor treatment to a particular cancer,” she said. “The findings may also tell us how cancer cells develop resistance so that these genes may be targets for intervention.”

—Staff writer Barbara B. Depena can be reached at barbara.b.depena@college.harvard.edu.