MRC1 and neoplasm: In this sense, murine J774 macrophages exposure to conditioned media from hypoxic tumor cells showed a protumor phenotype, promoted by the altered gene expression of Arginase-1 (Arg-1), inducible Nitric Oxide synthase (iNOS), and the M2 marker CD206, as well as anti-inflammatory interleukin 10 (IL-10) production (Figure 4A; conditioned media from hypoxic tumor cells (CH) vs. conditioned media from normoxic tumor cells (CN)).