IL6 and colonic neoplasm: Notably, the quality of the IL-6-mediated regulation of PD-L1 expression in colon tumor cells obviously depends on the source of IL-6 production, as the significant induction of this immunoregulatory molecule on the tumor cell surface could be detected in a similar manner either after the overexpression of IL-6 in the tumor cell compartment [87], after antibody-mediated systemic IL-6 blockade [92], or in the absence of IL-6 in the surrounding non-tumor cells [91].