The concentrations of IL-6 both in the patients with ovarian cancer and in the patients with benign ovarian tumors were significantly higher (p < 0.0001) in the peritoneal fluid than in the plasma (median 4198.18 vs. 21.72 pg/ml and 56.55 vs. 13.65 pg/ml, respectively). This evidence concerns the gene IL6 and ovarian benign neoplasm.