COL5A1 and gastric cancer: In this study, we explain and supplement the phenomenon in which miR-137-3p is inhibited in GC and its tumor-suppressive role: the low expression of miR-137-3p in GC leads to high expression of its target gene, COL5A1, which in turn can sponge miR-137-3p through a ceRNA mechanism to facilitate positive feedback regulation to further reduce miR-137-3p in GC.