To validate our hypothesis that tankyrase inhibition using small molecule inhibitors (XAV939 and WLX-8) is a feasible therapeutic approach for HCC, we further tested their ability to inhibit HCC cell proliferation using three HCC cell lines, which represent different molecular classes of the WNT/β-catenin pathway: HepG2 cells (which carry the truncated β-catenin mutation, partial exon 3 deletion) [24], Huh7 cells (which carry wild-type β-catenin) [9], and Hep40 cells (β-catenin status unknown, but responsive to WNT3A stimulation [data not shown]). Here, WNT3A is linked to hepatocellular carcinoma.