Various in vivo studies showed that fisetin alone performed anticancer activities against human colon cancer cell lines (CT‐26 and HCT116) and markedly down‐regulated the level of the oncoprotein securin in a p53‐independent manner, whereas fisetin in combination with 2‐Gy radiation did not significantly suppress securin‐null HCT116 tumor growth compared with normal HCT116 tumors (Leu et al., 2016). Here, PTTG1 is linked to malignant colon neoplasm.