Women with hereditary breast and ovarian cancer have genes that are also linked to a greater risk of heart disease, new research shows. A team at St. Michael's Hospital were surprised to discover the genes in question also regulate heart function.
A mutated form of the BRCA1 or BRCA2 genes, which normally suppress the growth of breast and ovarian tumours, was studied in mice. 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.
The researchers believe that the mutated BRCA1/2 prevents DNA repair in muscle cells that is essential to recovery after a heart attack. It is particularly sensitive to doxorubicin, a chemotherapy drug associated with heart failure.
Their findings were published in the journals Nature Communications and Journal of Biological Chemistry. The report concludes that breast cancer and heart disease share 'a common soil'.
"Our findings suggest that individuals who are at risk of breast cancer may also be at a previously unrecognized risk of heart disease," Dr Subodh Verma said.
"When a patient has the mutated gene, I now have to think about how much doxorubicin I'm going to give them or whether we should consider an alternate therapy."