Abstract A15: Noncanonical NF-kappaB signaling is associated with poor ovarian cancer prognosis

Abstract Objective: Mediated by a family of transcription factors, the canonical and noncanonical nuclear factor-kappaB (NF-kB) signaling pathways have key roles in inflammation, innate immunity, and cancer development and progression. As prior ovarian cancer studies have evaluated only canonical NF-kB transcription factors in relation to survival, this study was undertaken to evaluate both canonical and noncanonical NF-kB pathway components in tumor samples from epithelial ovarian cancer cases from the Vanderbilt Tissue Repository for Ovarian Cancer (TROC). Methods: We abstracted clinical data from electronic medical records and assayed p65 (representing the canonical NF-kB pathway) and p52 (representing the noncanonical NF-kB pathway) by immunohistochemistry for 197 TROC samples. Nuclear and cytoplasmic staining in tumor cells was semiquantified by H-scores and dichotomized at median values. Associations with progression-free survival (PFS) and overall survival (OS) were quantified by hazard ratios (HR) and 95% confidence intervals (CI) using Cox proportional-hazards regression. Results: Median cytoplasmic and nuclear p65 and p52 H-scores were significantly higher among high-grade and serous cases; median p52 H-scores were also significantly higher among late-stage cases and patients treated with chemotherapy (all Wilcoxon rank sum p<0.05). In unadjusted regression models, higher nuclear p65 and higher nuclear p52 were associated with approximately 40% and 70% shorter PFS and OS, respectively, but these associations were attenuated by adjustment for age, stage, tumor type, race, chemotherapy, and residual disease. In multivariable adjusted models, higher cytoplasmic p52 was associated with more than 50% shorter PFS (HR 1.68, 95% CI 1.18-2.39) and OS (HR 1.53, 95% CI 1.06-2.21). Furthermore, when cytoplasmic and nuclear staining were combined, and mutually adjusted models included both p52 and p65, only p52 remained associated with worse PFS (HR 1.57, 95% CI 1.10-2.37) and OS (HR 1.51, 95% CI 1.05-2.15). Conclusions: This is the first study to demonstrate that p52, representing noncanonical NF-kB signaling, may be an independent prognostic factor for epithelial ovarian cancer. Approaches to inhibit noncanonical NF-kB signaling should be explored as novel therapies for ovarian cancer are needed. Citation Format: Demetra Hufnagel, Andrew J. Wilson, Jamie Saxon, Dineo Khabele, Timothy Blackwell, Marta A. Crispens, Fiona Yull, Alicia Beeghly-Fadiel. Noncanonical NF-kappaB signaling is associated with poor ovarian cancer prognosis [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A15.