TCF4 and gastric cancer: Circ_SMAD4 promotes gastric cancer tumorigenesis by recruiting TCF4 to facilitate CTNNB1 transcription in the nucleus and sequestering miR-1276 in the cytoplasm to prevent the silencing of CTNNB1 mRNA, thereby activating the Wnt/β-catenin pathway (Wang L. et al., 2021).