Histopathological and molecular analyses of transbronchial biopsy specimens from the right middle lobe revealed adenocarcinoma; the malignant epithelial cells were positive for carcinoembryonic antigen (CEA) and negative for synaptophysin (Fig. 2), and they harbored an exon 19 deletion mutation in EGFR. The gene discussed is CEACAM5; the disease is adenocarcinoma.