Background: Recent studies have shown that multiple cytokines are secreted by ovarian epithelial cancer cells. Previous studies have shown that the cancer cell lines secrete macrophage colony-stimulating factor (M-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 (IL-1), interleukin-6 (IL-6), and transforming growth factor-alpha (TGF-alpha). Concomitantly, the serum levels of one of the growth factors (M-CSF) was found to be significantly elevated in patients with primary ovarian cancer and in second-look patients. The authors evaluated the serum levels of IL-1 alpha, IL-1 beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha) in patients with primary ovarian epithelial cancer. These levels were then compared with cytokine concentration found in normal peritoneal fluid.
Methods: Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of cytokines in normal peritoneal fluid, ascites, and serum.
Results: In serum, TNF-alpha and IL-6 were significantly increased in primary ovarian cancer patients when compared with control subjects (P < 0.0001 for both cytokines). TNF-alpha and IL-6 were also significantly higher than the levels found in second-look patients (P < 0.007 for TNF-alpha, and P = 0.0002 for IL-6). The levels of IL-1 alpha and beta were not elevated in ovarian cancer. TNF-alpha in the ascites was higher when compared with normal peritoneal fluid and was statistically significantly different when a cut-off point between 71-110 pg was selected (P < 0.005). The levels of IL-6 in ascites from patients with primary ovarian cancer also showed a marked increase (P < 0.0001) when compared with peritoneal fluid from control subjects.
Conclusions: Levels of IL-1, IL-6, and TNF-alpha were determined in normal peritoneal fluid, ovarian malignant ascites, normal serum, and serum from patients with ovarian cancer. This study showed that the patients with ovarian cancer have elevated levels of IL-6 and TNF-alpha in serum and ascitic fluid. A larger study would help in evaluating the potential use of cytokines as tumor markers in ovarian cancer.