Medical College of Georgia cancer researchers Dr. Ling Xia, a graduate exchange student, and Dr. Hernan Flores-Rozas said the genes offer protection against doxorubicin.

"We found a series of genes that are very important for cell survival in the face of doxorubicin," said Flores-Rozas. "At the moment you start inactivating these genes, the cells become very sensitive and don't grow any more. So now we know which genes we need to inactivate in the cell to make it very sensitive to the drug."

Doxorubicin is widely used to treat solid tumors in breast, prostate and ovarian cancers. A slightly modified version, daunorubicin, is a powerful fighter of leukemia and lymphoma in children.

The drugs can cause heart cells, called cardiomyocytes, can commit "suicide," or apoptosis, said Xia, a graduate student at China's Wuhan University.

The result is dilative cardiomyopathy, in which the heart can no longer pump blood. Damage can even appear years after chemotherapy has ended, with no treatment possible short of a heart transplant.

The study appears in the journal Cancer Research.