Immunocytochemical evaluation of human esophageal neoplasms and preneoplastic lesions for beta-chorionic gonadotropin, placental lactogen, alpha-fetoprotein, carcinoembryonic antigen, and nonspecific cross-reacting antigen.

Human esophageal neoplasms were studied in comparison to normal, uninvolved, and preneoplastic human esophageal epithelium for the presence of human chorionic gonadotropin (HCG), human placental lactogen (HPL), alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), and nonspecific cross-reacting antigen (NCA) using the unlabeled antibody peroxidase-antiperoxidase technique. HCG immunoreactivity was identified in 10 of 33 squamous cell carcinomas (33%), in 1 of 6 adenocarcinomas (17%), and 1 of 6 preneoplastic esophageal lesions (17%); while 9 of 33 squamous cell carcinomas (33%) and 1 of 6 adenocarcinomas (17%) contained immunoreactive AFP. Immunoreactive HPL was detected in 6 of 33 squamous cell carcinomas (20%), but in none of the adenocarcinomas. Neither AFP nor HPL immunoreactivity was identified in the 6 hyperplastic lesions which were studied. When stained with an antiserum that was able to detect both CEA and NCA, 27 of 33 squamous cell tumors (82%) and 6 of 6 adenocarcinomas (100%) showed positive immunostaining reactions. Of these, 8 squamous cell carcinomas and 1 adenocarcinoma were subsequently shown to contain only NCA immunoreactivity, while 19 squamous cell carcinomas and 5 adenocarcinomas contained both NCA and CEA immunoreactivity. NCA immunoreactivity alone was identified in 3 of 6 preneoplastic lesions and NCA and CEA immunoreactivity in 1 of 6 preneoplastic lesions. None of the markers was detected in 8 specimens of normal esophageal epithelium which were studied as controls, nor in 6 specimens of uninvolved esophageal epithelium obtained from patients with esophageal cancer. Most tumors expressed 2 or 3 markers, and some tumors were identified which expressed up to 4 of the 5 markers investigated. Only 3 tumors failed to express any of the markers studied. No association was found between the degree of tumor differentiation and presence or absence of HCG immunoreactivity. However, HPL immunoreactivity was more common in poorly differentiated squamous cell carcinomas. In contrast, immunoreactive AFP was more common in well-differentiated squamous cell carcinomas than in other tumor types. Similarly, both CEA and NCA were more frequently expressed in well-differentiated squamous cell carcinomas, adenosquamous carcinomas, and adenocarcinomas than in less differentiated tumors. Our results suggest that HCG, HPL, AFP, CEA, and NCA are tumor-associated antigens in esophageal cancer. Therefore, they could be of value in screening tests for esophageal neoplasms and could be useful in subclassification of esophageal neoplasms.