COL1A2 and gastric cancer: The collagen genes are often upregulated in GC; collagen type I alpha 1 chain (COL1A1) and collagen type I alpha 2 chain (COL1A2) upregulation are shown to be associated with poor survival, and collagen type IV alpha 1 chain (COL4A1) is shown to promote the progression of GC and multidrug resistance.