[EGFR-TKI response predictive marker, Prognostic marker]The PE level of soluble CDH3 (sCDH3) was increased in patients with resistance.The altered sCDH3 serum level reflected the efficacy of EGFR-TKI after 1 month of treatment (n = 43). Baseline sCDH3 was significantly associated with PFS and OS in patients with ADC after EGFR-TKI therapy (n = 76). Moreover, sCDH3 was positively associated with tumor stage in non–small cell lung cancer (n = 272). This evidence concerns the gene EGFR and lung cancer.