The expression of EFHD2 was significantly correlated with postsurgical recurrence of patients with stage I lung adenocarcinoma in the Kaplan-Meier-plotter cancer database search and our retrospective cohort study (HR, 6.14; 95% CI, 2.40–15.74; P < 0.001). The gene discussed is EFHD2; the disease is lung adenocarcinoma.