Corresponding to these results, the AUCs of RP5-977B1, CEA and CYFRA21-1 in the validation cohort were 0.8686 (P < 0.001), 0.6878 (P < 0.001) and 0.6361 (P = 0.0037) in distinguishing early-stage NSCLC from controls (Fig. 4D). This evidence concerns the gene CEACAM5 and non-small cell lung carcinoma.