CEACAM1 and lung carcinoma: Finally, the expression of CEACAM1-1, CEACAM1-3, and CEACAM1-3A was determined in a panel of 23 lung cancer cell lines derived from tumors of all the major histological subtypes (Additional file 2: Table S4), which demonstrated the expression of these three isoforms not only in NSCLC but also in small cell lung cancer (SCLC).