Among the factors associated with M1 polarization, the concentrations of IFN-γ in the peripheral blood of patients with stage II and stage IIIB-C colorectal cancer declined (one-way ANOVA, IFN-γ control vs stage II, p = 0.0158, control vs stage IIIB-C, p = 0.0485), suggesting that the M1 macrophage-mediated anti-tumor function was impaired in these two groups of colorectal cancer patients. Here, IFNG is linked to colorectal cancer.