Breast Cancer & Heart Disease May Share Common Roots

Women who are at risk for breast cancer may also be at greater risk for heart disease, report researchers from St. Michael's Hospital (Canada).  Observing that the majority of women with hereditary breast and ovarian cancer have a mutated form of the BRCA1 or BRCA2 genes, which normally suppress the growth of breast and ovarian tumors, Subodh Verma and colleagues have discovered that the genes also regulate heart function.  Following a heart attack, mice with the mutated BRCA1 gene had a three-to-five times higher rate of death. This was largely due to the development of profound heart failure, possibly because their heart attacks were twice as severe as those in mice who did not have the mutated gene.  A similar two-fold increase in heart failure was observed when mice with a mutated BRCA1 or BRAC2 gene were treated with doxorubicin, one of the most common chemotherapy drugs for patients with breast cancer. In addition to studies in mice, the authors also verified this observation in human tissues. The researchers believe that the mutated BRCA1/2 prevents DNA repair in muscle cells that is essential to recovery after a heart attack. Submitting that: “These data reveal BRCA1 as a novel and essential adaptive response molecule shielding cardiomyocytes from DNA damage, apoptosis and heart dysfunction,” the study authors conclude that: “BRCA1 mutation carriers, in addition to risk of breast and ovarian cancer, may be at a previously unrecognized risk of cardiac failure.”