Human chorionic gonadotrophin expression in colorectal adenocarcinoma.

The presence of human chorionic gonadotrophin (HCG) in colorectal adenocarcinoma was studied histologically in 45 tumors using immunoperoxidase technique. Ten neoplasms (22.2 percent) contained HCG-positive tumor cells. These cells were present mostly at the periphery of the tumors. Many formed parts of glands, while some were arranged in syncytial clumps or columns, or singularly. Thus, these tumor cells resembled trophoblastic tissue not only in being HCG-positive but also in their peripheral distribution and occasionally in morphologic appearance. HCG-positive tumors were seen more commonly in the rectosigmoid region (90 percent) and were more aggressive than HCG-negative tumors. In this study, lymph node or liver metastases were present in 70 percent of HCG-positive tumors compared with 29 percent of negative tumors--a difference which is statistically significant.