These populations are often distinguished by inducing stimuli (e.g., CSF-1, LPS, and IFN-γ for M1; GM-CSF, IL-4 and IL-13 for M2), secretion profiles (e.g., IL-12high, IL-6high, TNFαhigh, and CXCL9high for M1; IL-10high and TGF-β1high for M2), protein markers (e.g., HLA-DR and NOS2 for M1; CD163, CD204/MSR1/SR-A, CD206/MRC1, CD115/CSF-1R, and Arg1 for M2), and functional characteristics (e.g., antitumour or pro-tumour activity).44–46 CD11b and CD68 are among the markers commonly used to identify pan-monocyte/macrophages. Here, NOS2 is linked to neoplasm.