The carcinogenic effect of tobacco smoke on various organs is well recognized, and it accounts for about 50% increase in GC risk.21, 22 Previously, lots of studies have investigated the interaction between other genes and smoking on GC, including TNF, Exo1, CYP1A1, IL‐10, ERCC8, GSTP1, and hTERT.23, 24, 25, 26, 27, 28, 29 They all suggest genetic effects of gene polymorphisms on gastric carcinogenesis can be exacerbated by cigarette smoking. This evidence concerns the gene CYP1A1 and gastric cancer.