In our study we evaluated the percentage and distribution of Th17 cells in ovarian cancer patients in three different environments, i.e., peripheral blood, peritoneal fluid, and tissue (Th17 infiltrating ovarian cancer), as well as the concentration of proinflammatory cytokine IL-17A in plasma and PF in terms of their clinical and prognostic significance. The gene discussed is IL17A; the disease is ovarian carcinoma.