TCF4 and colorectal carcinoma: Recently, Liu et al. found that the lysine 64 residue (SHMT2K64) on SHMT2 and β-catenin and the transcription factor TCF4 interact to form SHMT2/β-catenin/TCF4 positive feedback loop, which inhibits ubiquitination-mediated degradation of β-catenin and promotes the proliferation and metastasis of CRC cells [29].