Fig. 2

The differentially expressed genes (DEGs) between the paired tumor and normal gastric tissues were detected. A Principal component analysis for the group of early-stage GC (EGC). B Principal component analysis for the group of advanced-stage GC (AGC). C Volcano plot of DEGs between EGC and paired para-tumor tissues. D Volcano plot of DEGs between AGC and paired para-tumor tissues. Note: the black data points represent genes that are not considerably changed, and the red data points and green data points signify the upregulated and downregulated genes in early GC (in comparison with paired para-tumor tissues) and advanced GC (in comparison with paired para-tumor tissues), respectively. |log2FC|> 1 and adj P < 0.05 were selected as the cut-off criteria. FC = fold change. E The intersection of upregulated DEGs of “EGC vs. Normal” and “AGC vs. Normal”. F The intersection of downregulated DEGs of “EGC vs. Normal” and “AGC vs. Normal.” “EGC vs. Normal” represents the differential expression analysis between EGC tissues and paired non-tumor tissues. “AGC vs. Normal” represents the differential expression analysis between AGC tissues and paired non-cancerous tissues