Human chorionic gonadotropin in gastric carcinoma. An immunohistochemical study suggesting independent regulation of subunits.

To investigate the production of human chorionic gonadotropin (hCG) in gastric carcinoma, 124 gastric carcinomas and a choriocarcinoma with adenocarcinoma were examined immunohistochemically, using anti-hCG alpha and beta antibodies. In choriocarcinoma, many trophoblastic cells were synchronously positive for both subunits. In contrast, the distribution of hCG-subunits in gastric carcinoma was unbalanced with hCG alpha in 39 and hCG beta in 63 cases. 26 cases contained alpha and beta positive cells, whereas synchronous cells were extremely rare in four cases. Incidences of hCG-subunit-positivities were not different between early and advanced carcinomas. HCG alpha-positive cells appeared endocrine-like in papillotubular carcinomas and some positive cells were argyrophilic in serial sections in 23 of 39 cases. HCG beta-positive cells were much more frequent in deranged glands, especially of microtubular-mucocellular carcinomas and most were not argyrophilic. In surrounding non-neoplastic mucosa, hCG alpha-positive cells were more numerous with endocrine-like configurations, but hCG beta-positive cells were rarely present in deranged glands. Although subunit-profile of hCG in gastric carcinomas was different from that of normal, the difference may be quantitative: hCG-subunits may be expressed through an independent mechanism but commonly in gastric mucosa and carcinoma. These results are also discussed in relation to trophoblastic tumours arising in non-trophoblastic tissues.