IL6 and neoplasm: I4 subtype has the poorest prognosis, possibly due to high levels of vascular factors (e.g. VEGF, FGF), chemokines (e.g. IL-6, TGF-β), and other factors produced by activated fibroblasts (e.g. αSMA), which may enhance pathways mediating primary tumorigenesis and inhibit immune cell recruitment into the tumor tissue.