CYFRA 21-1 is useful as a tumor marker, especially for non-small cell lung cancer (NSCLC) along with carcinoembryonic antigen (CEA) and squamous cell carcinoma–associated antigen (SCC) [2], [3], but also for other epithelial tumors such as bladder cancer [4]. Here, CEACAM5 is linked to non-small cell lung carcinoma.