IL-17 and VEGF are significantly associated with disease progression involving systemic inflammation in patients with gastric and colorectal cancers

Gastric and colorectal cancers are leading causes of death worldwide. Although a relationship between inflammation and the innate immunity in cancer-bearing hosts is widely accepted, the precise cell mechanisms mediating this relationship have not been elucidated. The aim of this study was to investigate the status of systemic inflammation, immune suppression, malnutrition, and prognosis associated with interleukin (IL)-17 and vascular endothelial growth factor (VEGF) in patients with gastric and colorectal cancers.The production of IL-17 and the serum levels of VEGF in patients with gastric and colorectal cancers were up-regulated in advanced stages of the diseases, which were positively correlated with the levels of myeloid-derived suppressor cells, the neutrophil-to-lymphocyte ratio, and C-reactive protein, while both were inversely correlated with IL-12 production, stimulation index, and nutritional markers including prealbumin and retinol binding protein. Overall survival of patients with stage III and IV gastric or colorectal cancer was significantly worse for patients with high IL-17 production or high VEGF levels than for those with low IL-17 production or low VEGF levels. The observations in the present study suggest that IL-17 and VEGF are closely associated with disease progression, and may serve as useful markers of the immune suppression, malnutrition, and prognosis in patients with gastric and colorectal cancers.