PPP4C and cancer: In future investigations, it would be fascinating to investigate the following: (1) whether Ppp4c promotes canonical Wnt signaling through endogenous Axin1 or not; (2) if so, whether this mechanism can be applied to the tumors identified in pan-cancer analysis; (3) the binding regulatory subunit(s) for Wnt activation and the PP4 assembly regulation; (4) if and how Ppp4c dephosphorylation correlates with Wnt/Tankyrase/RNF146-mediated AXIN degradation; and (5) whether Ppp4c regulates other Wnt axis levels and how these regulations interact.