We found that 23.4% (26/111) of normal_epi_colon highly expressed genes were aberrantly up-regulated in GC cells (Fig. S1B–D), such as goblet cell marker gene TFF3, claudin family genes (CLDN3, CLDN4 and CLDN7), transmembrane protein genes (TMEM176A and TMEM176B) and mucin gene (MUC13), which were shared by all GC patients in our study (Fig. S1C and D) and were validated in Human Protein Atlas data sets (https://www.proteinatlas.org/) (Fig. S1E). Here, CLDN3 is linked to gastric cancer.