Using cBioportal for Cancer Genomics (https://www.cbioportal.org/), the pan-cancer analysis demonstrated that KLK8 was significantly highly expressed in the tumor tissues compared with the normal samples in multiple cancer types, including COAD (Colon adenocarcinoma), ESCA (Esophageal carcinoma), LUAD (Lung adenocarcinoma), LUSC (Lung squamous cell carcinoma), READ (Rectum adenocarcinoma), STAD (Stomach adenocarcinoma), and THCA(Thyroid carcinoma) (Fig. 1a). This evidence concerns the gene KLK8 and gastric adenocarcinoma.