COL6A2 and gastric adenocarcinoma: Some genes in the network had been reported to be candidate biomarkers for STAD diagnosis and prognosis, such as biglycan (BGN), metalloproteinase-2 (TIMP2), adipocyte enhancer binding protein 1 (AEBP1), collagen type VI alpha 2 chain (COL6A2) and collagen type VI alpha 3 chain (COL6A3) (19–22), etc. The expression of VCAN and PDGFRB showed a significant linear relationship (Figure 7B), and both of them showed significant high expression levels at stage I of STAD tissues compared with that of normal tissues and maintained high expression levels after stage II (Figures 4D, E).