Salivais a practical diagnostic medium because collection is safe, simple and non-invasive [11].Measuring salivary CEA may help in early detection, monitoring and treatment assessment [12].Therefore, it is of interest to evaluate and compares salivary CEA levels in tobacco users, patients with OPMDs and oral cancer cases todetermine its diagnostic value and specificity as a salivary biomarker. The gene discussed is CEACAM5; the disease is lip and oral cavity carcinoma.