CEACAM5 and neoplasm: Iyoda et al. [18] analyzed the serum tumor markers of LCNEC and identified lactic dehydrogenase (LDH), tissue polypeptide antigen (TPA), CEA, and NSE as significantly increased, and α-fetoprotein (AFP), carbohydrate antigen 199 (CA199), and carbohydrate antigen 125 (CA125) to be elevated in only a few patients.