Occult residual ovarian tissue at the time of minimally invasive risk reducing surgery in women with BRCA mutations.

OBJECTIVE: To describe extension of ovarian tissue beyond visible and National Comprehensive Cancer Network recommended margins among patients with BRCA mutations undergoing minimally invasive risk-reducing salpingo-oophorectomy. METHODS: A prospective study of patients with BRCA mutations who underwent minimally invasive risk-reducing bilateral salpingo-oophorectomy was conducted. Patient enrollment occurred between October 2021 and 2023. Tissue specimens were analyzed according to the Sectioning and Extensively Examining the Fimbriated End protocol. RESULTS: Twenty women with BRCA mutations were prospectively enrolled. All patients underwent minimally invasive surgery with 70% undergoing concurrent hysterectomy (n = 14). Approximately half of these procedures were performed with robotic assistance (n = 9, 45%). One patient was admitted overnight (5%); the other nineteen were discharged on the day of surgery (95%). One patient experienced a major complication and required readmission (5%). Extension of ovarian tissue beyond the visible ovary was noted on pathologic examination of six specimens (30%). In one patient this was observed on the left (17%), in three on the right (50%), and in two bilateral extension (33%) was noted. The distance ovarian stroma extended microscopically beyond the visible ovary was between 2 and 14 mm, with a median of 5 mm. Among patients with microscopic extension of ovarian tissue, the majority (n = 5, 83%) had a BRCA2 mutation. CONCLUSION: In women with BRCA mutations undergoing risk-reducing minimally invasive surgery, approximately one third had microscopic extension of ovarian stroma beyond the visible ovary. Current guidelines which recommend resection of at least 20 mm of tissue beyond the visible ovary are likely adequate in this population.

BRCA Status Dictates Wnt Responsiveness in Epithelial Ovarian Cancer.

The association of BRCA1 and BRCA2 mutations with increased risk for developing epithelial ovarian cancer is well established. However, the observed clinical differences, particularly the improved therapy response and patient survival in BRCA2-mutant patients, are unexplained. Our objective is to identify molecular pathways that are differentially regulated upon the loss of BRCA1 and BRCA2 functions in ovarian cancer. Transcriptomic and pathway analyses comparing BRCA1-mutant, BRCA2-mutant, and homologous recombination wild-type ovarian tumors showed differential regulation of the Wnt/ß-catenin pathway. Using Wnt3A-treated BRCA1/2 wild-type, BRCA1-null, and BRCA2-null mouse ovarian cancer cells, we observed preferential activation of canonical Wnt/ß-catenin signaling in BRCA1/2 wild-type ovarian cancer cells, whereas noncanonical Wnt/ß-catenin signaling was preferentially activated in the BRCA1-null ovarian cancer cells. Interestingly, BRCA2-null mouse ovarian cancer cells demonstrated a unique response to Wnt3A with the preferential upregulation of the Wnt signaling inhibitor Axin2. In addition, decreased phosphorylation and enhanced stability of ß-catenin were observed in BRCA2-null mouse ovarian cancer cells, which correlated with increased inhibitory phosphorylation on GSK3ß. These findings open venues for the translation of these molecular observations into modalities that can impact patient survival. SIGNIFICANCE: We show that BRCA1 and BRCA2 mutation statuses differentially impact the regulation of the Wnt/ß-catenin signaling pathway, a major effector of cancer initiation and progression. Our findings provide a better understanding of molecular mechanisms that promote the known differential clinical profile in these patient populations.