ABCC2 rs717620 was significantly associated with chemotherapy response for adenocarcinoma patients (additive model: OR 0.55, 95% CI 0.31–0.96, P = 0.036; dominant model: OR 0.41, 95% CI 0.22–0.79, P = 0.007), patients >55 years of age (dominant model: OR 0.43, 95% CI 0.23–0.82, P = 0.010), smoker patients (additive model: OR 0.46, 95% CI 0.27–0.80, P = 0.006; dominant model: OR 0.40, 95% CI 0.22–0.73, P = 0.003), and male patients (additive model: OR 0.60, 95% CI 0.38–0.94, P = 0.027; dominant model: OR 0.51, 95% CI 0.30–0.86, P = 0.011). The gene discussed is ABCC2; the disease is adenocarcinoma.