For lung adenocarcinoma, CTAPIII/CXCL7 showed the highest AUC (Fig. 2A, training set: AUC 0.800, 95% CI: 0.737–0.861; Fig. 2B test set AUC 0.775, 95% CI: 0.709–0.842) and satisfactorily separated the patients with lung adenocarcinoma from controls. This evidence concerns the gene PPBP and lung adenocarcinoma.