TP53 and colorectal carcinoma: Given that CSCs share characteristics with ISCs, we investigated whether the most essential niche factors WNT3 and R-spondin1 for maintaining the activation of the WNT/β-catenin pathway of ISCs were involved in the p53-mediated activation of the WNT/β-catenin pathway and CSC activation in 5-FU-treated CRC.