IL-17 and VEGF are increased and correlated to systemic inflammation, immune suppression, and malnutrition in patients with breast cancer

Abstract

Relationships between inflammation and innate immunity in cancer are widely accepted today; however, the precise cell mechanisms mediating these relationships have not yet been elucidated. Interleukin (IL)-17 is a proinflammatory cytokine that has been reported to induce inflammation in patients with autoimmune diseases. Myeloid-derived suppressor cells (MDSC) may contribute to the negative regulation of immune responses during cancer and inflammation. Vascular endothelial growth factor (VEGF) is reported to have multiple biological actions including increasing vascular permeability, neovascularization, and possible inhibition of immune function in malignant diseases. This study investigated the status of systemic inflammation and immune suppression associated with IL-17 and VEGF in patients with breast cancer. IL-17 production and the serum levels of VEGF were also increased in advanced stages of the disease. The production of IL-12, which induces Th1 cells, and the stimulation index (SI), which is a marker of cell-mediated immune function, were both shown to decrease along with disease advancement. Also, the production of IL-17 and the VEGF levels were both positively correlated with the levels of MDSC, the neutrophil-to-lymphocyte ratio (NLR), and C-reactive protein (CRP), and were inversely correlated with IL-12 production and the SI. Nutritional markers, including prealbumin (PA), transferrin (TF), and retinol-binding protein (RBP), were also shown to be significantly lower in patients with high production of IL-17 or high levels of VEGF. These data clearly showed that IL-17 and VEGF, whose levels correlated with each other and with those of MDSC, were significantly associated with disease advancement, systemic inflammation, suppression of cell-mediated immunity including Th1 induction, and malnutrition.