IGFBP2 and lung cancer: When stratifying lung cancer by tumor stage, the AUC for lung cancer I–II and lung cancer III–IV was 0.656 (95% CI=0.568–0.743; P= 0.001) and 0.685 (95% CI= 0.615–0.755; P<0.001) (Fig. 2E and F), respectively, indicating some ability of anti-IGFBP-2 antibodies to diagnose lung cancer.