Although the CEACAM5 glycoprotein has been extensively studied and validated in the management of various gastrointestinal malignant neoplasms, the same cannot be said in lung cancer.21,25 Literature reports17,18,23,27,28 demonstrate variable expression of the glycoprotein in lung cancer, and significant geographic variables are associated with the data. The gene discussed is CEACAM5; the disease is lung carcinoma.