Ovarian cancer is the most fatal gynecological cancer with high mortality. It still has no reliable diagnostic marker and effective treatment due to its high drug resistance and high recurrence. To develop a novel biomarker for diagnosis and therapeutic target of intractable ovarian cancer, we selected for an upregulated gene in serous ovarian tumors compared with normal ovary counterparts by microarray analysis and confirmed its elevated mRNA expression in ovarian tumors by RT-PCR. Consistent with its high mRNA level, tumor-specific preferential high expression of candidate protein was detected in the cytoplasm of the ovarian tumor tissues by immunohistochemistry. To our surprise, indirect immunofluorescence staining revealed an unexpected cytoplasmic subcellular localization of a candidate protein. Furthermore, forced expression of a candidate gene in cultured cells with no detectable level showed a marked inhibition of cell proliferation. To address these unexpected findings, we set out to identify a candidate interacting protein by yeast 2-hybrid screening to explore a novel function and its underlying mechanism. Among them, one of cell death associated protein was identified as a novel interacting partner of a candidate protein and their physical interaction in mammalian cells was confirmed by co-immunoprecipitation assay and confocal microscopy. Further domain mapping analysis should reveal critical domains for their interaction and would provide fundamental and pivotal information for a novel function and an underlying molecular mechanism of a candidate gene. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2018R1D1A1B07047640).

Citation Format: Kyoungsook Park, Chaeyeon Son, Sang Yong Song. IDENTIFICATION OF A NOVEL CANDIDATE BIOMARKER FOR DIAGNOSIS AND THERAPEUTIC OVARIAN CANCER TARGET [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr GMM-044.