Dr. Borst on Homologous Recombination Deficiency in Patients With Ovarian Cancer

Matthew Borst, MD, director, GYN/Oncology, Banner Good Samaritan Regional Medical Center, clinical assistant professor of medicine, University of Arizona, Arizona Oncology, discusses homologous recombination deficiency (HRD) in patients with ovarian cancer.

Everyone has BRCA1/2 genes which help repair double-strand DNA breaks that people encounter in daily life. If a patient has germline BRCA1/2 abnormalities, they have an intrinsic vulnerability to not repair double-strand breaks. About 50% of high-grade serous ovarian cancers have HRD or BRCA abnormalities in the somatic tumor.

That is something that physicians can take advantage of therapeutically by adding a PARP inhibitor, which inhibits the ability to repair single-strand breaks. Over time, the tumor cells accumulate multiple single-strand breaks, which will convert to double-strand breaks because they lack intact or wild-type BRCA capabilities. Subsequently, the tumor cells preferentially die, says Borst.