OSTF1 and ovarian cancer: In the first step of our study, expression of the OSF-2 gene in the following ovarian cancer cell lines was examined: high-grade serous—OVCAR3, PEA1, PEA2; low-grade serous—PEO23; serous—SKOV-3; endometroid adenocarcinoma - A2780 and primary ovarian cancer cell line—W1.