We did Gene Set Enrichment Analysis (GSEA) [15, 16] using TCGA Stomach Cancer gene expression RNAseq data and found that high expression level of either TFAP2A or PLS3 are associated with the activation of cancer-related pathway in gastric cancer patients (Fig. 5a); whereas the top positively enriched KEGG pathways for PSMB8 were less associated with cancer (Figure S4B). Here, PSMB8 is linked to medical procedure.