Upon entering the tumour microenvironment (TME), the recruited monocytes encounter a wide array of physical (e.g., hypoxia and ECM proteins), chemical (e.g., cytokines (e.g., IL-6), and metabolic (e.g., lactic acid, adenosine, and arginine)) factors known to influence monocyte/macrophage phenotypes [35,36,37]. This evidence concerns the gene IL6 and neoplasm.