In addition, CK1δ can phosphorylate MDM2, reduce its interaction with p53, and further stabilize and activate p53 46.However, the effect of CK1ε/δ inhibitors IC261 on the expression of p53 in colon cancer cells remains unclear.Our results show that IC261 can significantly reduce the level of p53 protein in colon cancer cells. This evidence concerns the gene MDM2 and malignant colon neoplasm.