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<i>Background</i>: Reversion mutations in <i>BRCA1/2</i>, resulting in restoration of the open reading frame, have been identified as a mechanism of resistance to platinum-based chemotherapy or PARP inhibition. We sought to explore the incidence of <i>BRCA1/2</i> reversion mutations in different tumor types. <i>Methods</i>: We retrospectively analyzed molecular profiling results from primary and/or metastatic tumor samples submitted by multiple institutions. The samples underwent DNA and RNA sequencing at a CLIA/CAP-certified clinical lab. Reversion mutations were called only in patients whose available clinical records showed the use of PARP inhibitors or platinum agents prior to tumor profiling. <i>Results</i>: Reversion mutations were identified in 75 of 247,926 samples profiled across all tumor types. Among patients carrying pathogenic or likely pathogenic <i>BRCA1/2</i> mutations, reversion mutations in <i>BRCA1/2</i> genes were seen in ovarian cancer (OC) (30/3424), breast cancer (BC) (27/1460), endometrial cancer (4/564), pancreatic cancer (2/340), cholangiocarcinoma (2/178), prostate cancer (5/461), cervical cancer (1/117), cancer of unknown primary (1/244), bladder cancer (1/300), malignant pleural mesothelioma (1/10), and a neuroendocrine tumor of the prostate. We identified 22 reversion mutations in <i>BRCA1</i> and 8 in <i>BRCA2</i> in OC. In BC, we detected 6 reversion mutations in <i>BRCA1</i> and 21 in <i>BRCA2.</i> We compared molecular profile results of 14 high-grade serous ovarian cancers (HGSOC) with reversion mutations against 87 control HGSOC with pathogenic <i>BRCA1/2</i> mutations without reversion mutations. Tumors with reversion mutations trended to have had lower ER expression (25% vs. 64%, <i>p</i> = 0.024, q = 0.82) and higher <i>KDM6A</i> mutation rate (15% vs. 0, <i>p</i> = 0.016, q = 0.82). <i>Conclusions</i>: We present one of the largest datasets reporting reversion mutations in <i>BRCA1/2</i> genes across various tumor types. These reversion mutations were rare; this may be because some patients may not have had repeat profiling post-treatment. Repeat tumor profiling at times of treatment resistance can help inform therapy selection in the refractory disease setting.