ARG1 and malignant colon neoplasm: In a preclinical study of colon cancer cells, conditioned media of colon cancer cell lines whose EGFR expression was knocked down led to down-regulation of M2 macrophage-related markers such as IL-10, Arg1, CCL17, CCL22, and IL-4, while up-regulating M1 macrophage-related markers including IL-12, CCR7, and TNF-α at the same time18.