- Background/Aim: It has been previously shown that epithelial ovarian carcinoma tissues express high levels of tumor necrosis alpha (TNF-α), interleukin (IL)-6, IL-1α and IL-1β. The aim of the present study was to evaluate the localization of TNF-α and its receptors (TNFR1 and TNFR2) in different types of ovarian carcinoma tissues and the possible role of TNF in the pathogenesis of epithelial ovarian carcinoma. Total RNA was extracted from normal and cancerous ovarian tissues and mRNA was analyzed with semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Immunohistochemical staining was performed with use of antibodies against human (ah)TNFR1 and TNF2. TNF-α mRNA and TNFR2 mRNA levels were significantly higher in ovarian carcinoma tissues than in normal ovarian tissues, whereas TNFR1 mRNA levels were similar. TNFR1 and TNFR2 were mainly localized in the epithelial neoplastic cells of the tumor. Knocking-down TNF-α activity with αhTNF-a altered ovarian carcinoma cell morphology (with more branches) in vitro. Our study indicates a possible role of TNF-α in epithelial ovarian carcinoma pathogenesis through TNFR2, which affects morphological changes, which may be involved ovarian cancer pathogenesis.