An immunohistochemical study of keratin, carcinoembryonic antigen, human chorionic gonadotropin and alpha-fetoprotein in lung cancer.

Immunohistochemical staining utilizing a peroxidase-antiperoxidase (PAP) technique for keratin, carcinoembryonic antigen (CEA), human chorionic gonadotropin (HCG) and alpha-fetoprotein (AFP) was performed on paraffin sections from 72 cases of lung cancer obtained at autopsy. Positive reaction was shown in 44% of the cases for keratin, 77% for CEA, and 58% for HCG. AFP was positive in only one case of large cell carcinoma. Keratin was positive in 100% of squamous cell carcinoma, 53% of adenocarcinoma, 15% of small cell carcinoma and 45% of large cell carcinoma. CEA showed positive staining in 90% of squamous cell carcinoma, 88% of adenocarcinoma, 58% of small cell carcinoma and 69% of large cell carcinoma. CEA was the most useful tumor marker for detection of all types of lung cancer. HCG was positive in 30% of squamous cell carcinoma, 100% of adenocarcinoma, 23% of small cell carcinoma and 56% of large cell carcinoma.