Then, to examine the diagnostic and prognostic value of CLDN6, we performed the ROC curve and the Kaplan–Meier survival curve in pan-cancer and found that CLDN6 had a certain accuracy (AUC > 0.7) in predicting 15 cancer types, especially had a high accuracy (AUC > 0.9) in predicting LAML, TGCT, OV, and UCS. This evidence concerns the gene CLDN6 and cancer.