Gene behind breast cancer may also cause heart disease

Dr. Subodh Verma, a cardiac surgeon at St. Michael's Hospital, said his research team was surprised to discover 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.

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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.

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In addition to studies in mice, the authors also verified this observation in human tissues.

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The researchers believe that the mutated BRCA1/2 prevents DNA repair in muscle cells that is essential to recovery after a heart attack.

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"Our findings suggest that individuals who are at risk of breast cancer may also be at a previously unrecognized risk of heart disease," Dr. Verma said.

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"More importantly, we now understand that breast cancer and heart disease -- the two leading causes of death for Canadian women - have a common biological basis, a common soil," he added.

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Their findings were published in the journals Nature Communications and Journal of Biological Chemistry.u00a0