The AUC of using anti-IGFBP-2 antibodies as diagnostic biomarkers for lung cancer was 0.677 (95% CI=0.610–0.744; P<0.0001) (Fig. 2A), in contrast to an AUC for CEA, CYFRA21-1 and NSE of 0.770 (95% CI= 0.688–0.853, P<0.0001), 0.794 (95% CI= 0.719–0.864, P<0.0001) and 0.588 (95% CI= 0.490–0.586, P= 0.104), respectively, for cancer in our patient cohort (Fig. 2A–D). Here, CEACAM5 is linked to cancer.