CEACAM5 and squamous cell carcinoma: An analysis of the patient’s serum revealed the following findings: squamous cell carcinoma (SCC), 3.4 ng/mL (normal range, < 1.5 ng/mL); carcinoembryonic antigen (CEA), 50.0 ng/mL (normal range, < 5 ng/mL); and carbohydrate 19-9 antigen (CA19-9), 1 U/mL (normal range, < 37 U/mL).