APC and cancer: Since the activation of Wnt signaling caused by β-catenin, APC or Axin1 mutation is a common event in the great majority of colon cancer and in a subset of HCC [12, 13], we chose four cancer cell lines for subsequent experiments; two colon cancer cell lines, HCT116 and SW480, harboring β-catenin mutation and APC mutation, respectively, as well as two HCC cell lines, SNU449 and SNU475, with β-catenin mutation and Axin1 mutation, respectively.