IL6 and neoplasm: Inhibiting the expression of PD-1 in tumors leads to increased levels of IL-6 and IL-17 in the peripheral blood; because the main function of IL-6 and IL-17 is to promote neutrophil-mediated inflammation, this may weaken the anti-tumor immune response (Fielding et al., 2008; Miossec and Kolls, 2012).