CTNNB1 and cancer: This mutation is a missense mutation in all transcripts, causing the 41st amino acid of the CTNNB1 encoded protein β-catenin to change from threonine to alanine (p.T41A), disrupting the GSK3 β phosphorylation site (a key site in the degradation signaling pathway), preventing the normal degradation of β-catenin, leading to abnormal protein accumulation and sustained activation of the Wnt signaling pathway, promoting cell proliferation, and ultimately leading to cancer.