In TCGA database tumor paired samples, compared with normal tissues, the expression of CLDN12 in bladder urothelial carcinoma (BLCA), COAD, esophageal carcinoma (ESCA), KICH, hepatocellular carcinoma (LIHC), lung squamous cell carcinoma (LUSC), KIRC, prostate adenocarcinoma (PRAD), rectal adenocarcinoma (READ), stomach adenocarcinoma (STAD) and KIRP tumor tissues was significantly different (P < 0.05) (Figure S4). Here, CLDN12 is linked to gastric adenocarcinoma.