CEACAM5 and lung cancer: It is normally expressed in epithelial cells of the fetal gastrointestinal tract (132, 133); however, non-small-cell lung carcinoma (NSCLC) patients have elevated CEA serum levels, something that has been correlated with low survival rates (13, 134) so that CEA promoter has been used in directing E gene (pCEA-E) along with (PTX) in order to specifically target lung cancer cells, improving anti-tumor effects of PTX.