Through Kaplan–Meier survival analysis, we found that the upregulated CASK expression at both the mRNA and protein levels was significantly related to a better prognosis in CCA patients and that CCA patients with high CASK expression at the protein level had a longer recurrence-free survival rate, which means that low CASK expression is an independent prognostic risk factor in CCA patients. This evidence concerns the gene CASK and cholangiocarcinoma.