Abstract One of the most important challenges in the ovarian cancer research is to identify new molecular pathways that can be targeted to kill ovarian cancer cells. High-grade serous ovarian cancer (HGS-OvCa) cells survive, proliferate, and assemble into multicellular clusters that have a capacity to disseminate within the peritoneum. Therefore, it is important to identify specific molecular mechanisms that can be targeted to block survival, growth, and assembly of ovarian cancer multicellular clusters that metastasize within peritoneum. High-grade ovarian tumors originate from the fallopian tube epithelium (FTE) and almost all have mutations in theTP53 gene. The contribution of various mutant p53 proteins (m-p53) to ovarian cancer and whether targeting mutant p53 –dependent molecular mechanisms in ovarian cancer is poorly understood and of clinical significance. We have developed new methodologies and used them to identify m-p53-dependent pathways that support HGS-OvCa survival, proliferation and assembly of multicellular aggregates under condition mimicking peritoneal suspension. To determine whether mutations in TP53 contribute to the ability of HGS-OvCa cells to survive, proliferate, and assemble into multicellular clusters we introduced different variants of mutant p53 (m-p53) into normal human non-transformed FTE cells. We found that expression of m-p53 variants (R175H; R249S; R273H) in FTE cells promoted survival, growth, and assembly of multicellular clusters under conditions mimicking peritoneal suspension. Interestingly m-p53-driven phenotypes were not induced by the loss of p53 expression; and more importantly, these phenotypes were blocked by the reactivation of p53 pathway with small molecule inhibitor NSC319726. We further found that m-p53 induced phenotypes were dependent on the expression of integrin β 1 (ITGB1). The evidence that activated ITGB1 is enriched at cell's surface of precursors of HGS-OvCa within the fallopian tube and HGS-OvCa isolated from ovarian cancer patients highlighted the relevance of these findings to ovarian cancer. We hypothesize that mutant p53 supports survival, growth, and assembly of multicellular HGS-OvCa clusters through mechanisms in which ITGB1 plays a critical role. Our data indicate that observed phenotypes are the consequence of the m-p53 gain of function mechanisms that are amenable to therapeutic inhibitions and targeting m-p53 in HGS-OvCa might be of clinical significance. Citation Format: Marcin P. Iwanicki, Marian Novak, Ioannis K. Zervantonakis, Tan A. Ince, Ronny Drapkin, Joan S. Brugge. Targeting mutant p53 and cell-cell adhesion in ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A7.