Patients with a variety of tumors present to the physician because of clinical manifestations of hormones secreted in excess. This phenomenon attracted the investigative interest of such pioneers as Harvey Cushing who recognized that pituitary tumors may cause acromegaly and Charles Mayo who associated hyper tension with adrenal medullary neoplasms. Current int rest in endocrine-related tumors has intensified because of the explosive development of newer methodol ogy for their study. Specific measurements of secretory products, hybridization assays to identify products of genomic translation...