Among three 5-hydroxy polymethoxyflavones (5OH-PMFs), 5-hydroxy-3,6,7,8,3′,4′-hexamethoxyflavone (5HHMF), 5-hydroxy-6,7,8,3′,4′-pentamethoxyflavone (5HPMF), and 5-hydroxy-6,7,8,3′,4′-pentamethoxyflavone (5HTMF), the data showed that the 5HTMF-induced G0/G1 arrest was the most responsive to the change of the p21 and p53 status of the colon cancer cells, indicating the essential role of the 4′-methoxyl group on B ring of 5HTMF in inducing cell cycle arrest [26]. The gene discussed is TP53; the disease is malignant colon neoplasm.