NOS2 and ovarian carcinoma: For instance, a positive effect of STAT1 in ovarian cancer was that it upregulated the expression of inducible nitric oxide synthase (iNOS) (13), resulting in the release of cytotoxic nitric oxide (NO) (14) and accelerating the progression of the disease (15); however, NO could also promote ovarian cell apoptosis by increasing the expression of p53 (16).