IL10 and neoplasm: Although peripheral blood myeloid cells are predominantly nonpolarized prior to tumor entry (8), they can release immunosuppressive cytokines (7, 9) (e.g. TGFβ, IL-10), secrete cancer proliferating growth factors (7, 10, 11) (e.g. EGF, HGF, PDGF, VEGF), inactivate cytotoxic T cells via T cell receptor nitrosylation (1, 8), exude nucleotide bases that facilitate cancer cell mitosis (12), promote tumor metastasis (6, 13, 14), and stimulate extracellular matrix deposition that can obstruct drug and immune cell penetration (15) following accumulation in tumor masses.