NOS2 and cancer: Furthermore, at the gene and protein level M1 Mφs express and release the pro-inflammatory mediators: nitric oxide synthase 2 (NOS2), IL-12, nitric oxide (NO), IL-1β, C-X-C motif ligand 10 (CXCL10) and tumour necrosis factor-α (TNF-α), exhibiting anti-leukaemia and immunostimulatory functions, and importantly enhancing cancer drug sensitivity (Yuan et al., 2015).