In subgroup analyses by cancer location, a significant positive additive interaction between the PRKAA1 rs13361707 genotype and HP infection was observed in cardia gastric cancer (RERI, 1.25; 95% CI: 0.08–2.41; P = 0.036), whereas borderline significance was observed in noncardia gastric cancer (RERI, 0.66; 95% CI: −0.11–1.43; P = 0.092). The gene discussed is PRKAA1; the disease is gastric cardia carcinoma.