To determine whether NR4A1 plays important roles in the TME, we implanted three syngeneic tumors into wild-type (WT) or NR4A1−/− (KO) mice, including the MC38 colon cancer model, and Yummer1.7 and B16F10, the two melanoma models. Here, NR4A1 is linked to malignant colon neoplasm.