CDK4 and cholangiocarcinoma: We demonstrated that suppression of C1GALT1 in CCA cell lines contributed to various CCA aggressive malignant phenotypes, including cell growth and 5-FU resistance through increased transcription levels of growth-related genes (CCND1, CDK4, CCNE1, and c-MYC) and the ABC transporter superfamily (ABCC1, ABCC3, and ABCG2).