Human chorionic gonadotropin production by colon carcinoma. Biochemical heterogeneity and identification of a chemotherapy‐sensitive cell subpopulation

Human chorionic gonadotropin (hCG) is produced and secreted by a wide variety of human neoplasms and represents one example of biochemical heterogeneity in tumors. The authors report two patients with advanced hCG‐producing colon carcinomas in whom immunohistochemical staining demonstrated a distinct hCG‐producing cell subpopulation. Both patients had objective tumor responses when treated with chemotherapy effective against germinal neoplasms. Responses were characterized by prompt and substantial reduction in plasma hCG levels and by improvement in clinical status, radiographic tumor measurements, and other biochemical abnormalities. These epithelial carcinomas responded to chemotherapeutic agents that are usually ineffective, and striking chemosensitivity was observed in the hCG‐producing cell subpopulation. These two cases provide initial evidence that hCG‐producing cells are sensitive to certain chemotherapeutic agents even when they are a part of common epithelial somatic tumors, and that this sensitivity represents another type of heterogeneity in human tumors. The identification of hCG production in epithelial tumors may be important in determining therapeutic strategy.