STAT3 and neoplasm: Several studies have shown that tumor-infiltrating lymphocytes and myeloid cells display constitutive STAT3 phosphorylation, including T cells, DCs, neutrophils, macrophages, and NK cells, which is often driven by the production of cytokines and growth factors by both tumor cells and the infiltrating cells themselves, such as IL-6, IL-10, VEGF, and HGF, among others (55).