A variation of a cancer-causing gene called SNP309 interacts with an anti-cancer gene, known as p53, to influence a woman's odds of surviving breast cancer, according to a report in the Journal of the National Cancer Institute.

Dr. Stefan Ambs, from the National Cancer Institute, Bethesda, Maryland, and colleagues investigated whether SNP309 was associated with breast cancer risk and outcome and whether it interacted with p53 to affect survival.

Alone, SNP309 did not affect survival, but in combination with certain p53 changes, it seemed to reduce survival.

Researchers have begun developing drugs that target the proteins produced by p53, Ambs said. "Depending on the status of SNP309, a patient may respond well or may not have a good response to those or other drugs. Thus, the relationship between SNP309 status and the response to treatment should be studied."