SLCO2A1 and gastric cancer: In this study, seven genes (SLCO2A1, SHISA2, SERPINE1, SMPD3, GPC3, CRABP2, C1QTNF5) were used for the construction of OE_score, among which SLCO2A1, SERPINE1, CRABP2, and GPC3 were reported to be associated with gastric cancer (41–44), and play an important role in the occurrence and development of gastric cancer.