Cytokine status in the omentum and peritoneum in metastatic gastric cancer.

Abstract

e16557 Background: Gastric cancer (GC) is one of the most common malignant tumors and the second most common cause of cancer deaths in Russia. Many researchers note the ambiguous role of cytokines in the pathogenesis of tumor processes. The purpose of the study was to determine characteristics of the cytokine status in the omentum and peritoneum of patients with metastatic GC. Methods: The main group (Mgr) included 23 patients with T2-4N0-3M1 GC with metastases to the peritoneum and greater omentum, the mean age 58.9±9.7 years. The comparison group (Cgr) included 20 non-cancer patients, the mean age 55.9±9.7 years. Tissues of the omentum (OT) and peritoneum (PT) were obtained from all patients during cytoreductive and diagnostic surgeries. Ex tempore tissues were disintegrated using BD Medimachine (USA) with 0.9% NaCl; the cell suspension was centrifuged, and the supernatant was collected and aliquoted. Levels of cytokines IL-1β, IL-2, IL-6, IL-8, IL-18, TNF-α, IL-10 (Vektor-Best, Russia) and IL-1RA (eBioscience, Austria) were determined by ELISA. The results were expressed as the specific content per 1 g of protein evaluated by the biuret method (pg/mL/g of protein). Statisical analysis of the results was performed with the Statistica 10 program (StatSoft Inc., USA). Significance of differences was evaluated using the Mann-Whitney and Wilkinson tests; differences were considered significant at p < 0.05. Results: In Cgr, levels of IL-6, IL-8, IL-18 and IL-1β in OT were 4.1±1.1, 3.4±0.7, 21.2±5.5 and 10.8±2.1, while in Mgr – 55.3±24.4, 32.5±13.8, 144.9±48.4 and 21.01±5.4 pg/mL/g of protein, i.e. 13.7, 9.5, 6.9 and 1.9 times (p≤0.05) higher than in Cgr, respectively. The specific content of IL-1RA in OT was 12.6 times higher, p≤0.05 (215.7±69.8 vs. 2723.1±730.1), and the IL-10 concentration did not differ significantly. In PT of Cgr, levels of IL-8, IL-18 and IL-6 were 9.8±7.3, 35.2±21.7, 7.5±3.7, and in Mgr – 250.7±21.4, 322.9±16.9, 61.1±27.6 pg/mL/g, i.e. 25.7, 9.2 and 8.2 times (p≤0.05) higher than in Cgr. IL-1RA in PT of Mgr was 24.4 times higher than in Cgr, p≤0.05 (7656.2±3160.3 vs. 357.69±180.86). Conclusions: A certain microenvironment is formed in OT and PT affected by metastases, with specific features in the ratio and concentrations of various cytokines, which undoubtedly contribute to the formation of a secondary tumor.