CEACAM5 and squamous cell carcinoma: Levels of tumor markers alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), squamous cell carcinoma (SCC) antigen, pro-gastrin-releasing peptide (Pro-GRP), and prostate-specific antigen (PSA) were within the normal range.