Alpha-human chorionic gonadotropin and neuron-specific enolase as markers for malignancy and neuroendocrine nature of pancreatic endocrine tumors.

Human chorionic gonadotropin (HCG) or its alpha and beta subunits have been proposed as markers for malignancy in pancreatic endocrine tumors. Since proof of malignancy of pancreatic endocrine tumors is difficult early in the course of the disease, we tested retrospectively a series of 157 pancreatic endocrine tumors for the presence of alpha- or beta-HCG by immunocytochemistry. In addition, antiserum against neuron-specific enolase (NSE) was applied to these tumors, in order to demonstrate their neuroendocrine nature, alpha-HCG-immunoreactive cells were present in 42/56 (75%) functioning malignant pancreatic endocrine tumors, but in only 1, possibly benign, glucagonoma out of 67 functioning benign tumors, in only 1/17 nonfunctioning malignant, and in 0/17 nonfunctioning benign tumors. We were not able to localize beta-HCG-immunoreactivity in the tumors. In all but 1 tumor NSE was observed. It is concluded that alpha-HCG represents a reliable marker for malignancy in functioning pancreatic endocrine tumors, and that the presence of NSE establishes the neuroendocrine nature of the tumors.