To understand whether calpain-8 and calpain-9 were involved in gastric carcinogenesis, we first screened differentially expressed genes and examined the mRNA expression patterns of calpain family in gastric cancer tissues from reported GEO13 and TCGA-STAD14 datasets (Supplementary Fig. S1 and Supplementary Table S1). The gene discussed is CAPN9; the disease is gastric cancer.