AXIN1 and colorectal carcinoma: To test whether TCF4 regulates SHMT2 transcription by the Wnt/β-catenin pathway, CRC cells were treated with two inhibitors of Wnt pathway components, XAV939 (inhibiting Tankyrase, thereby stabilizing Axin1) and iCRT14 (disrupting the β-catenin-TCF4 interaction).