Because hormones produced by malignant tumors are often identified and quantified by immunoassays designed to measure typically produced hormones, elevation of a given hormone is not considered diagnostic of a specific tumor. While these assays are highly sensitive, their lack of specificity limits their utility as a screening tool.
| Hormone | Type of Cancer | Comments |
| Adrenocorticotropic hormone (ACTH) | Lung (small cell) | ACTH is usually produced by the corticotropic cells of the anterior pituitary. It may be accompanied by excessive production of cortisol, traditionally associated with Cushing’s syndrome. |
| Antidiuretic hormone (ADH) | Lung (small cell), adrenal cortex, pancreatic, intestine | ADH helps to regulate water balance in the blood. Typically, ADH is elevated in response to high blood osmolality. Measuring ADH about plasma osmolality increases its sensitivity as a tumor marker. |
| Calcitonin | Thyroid, lung, breast, renal, liver | They are secreted in response to increased serum calcium to inhibit calcium release from bone. |
| Gastrin | Gastrinoma | Fasting plasma gastrin is often significantly increased to several times the standard upper limit. Considered diagnostic as a tumor marker when elevated 10 times the upper limit of normal in the presence of gastric hypersecretion. |
| Glucagon | Glucagonoma (islet-cell pancreatic tumor | Highly metastatic. Feedback mechanisms do not control sustained elevated glucose levels as glucagon is produced. |
| Human chorionic gonadotropin (hCG) | Embryonal, placenta, testicular, choriocarcinoma | They are typically elevated during pregnancy. hCG is produced and is highly elevated in trophoblastic or chorionic tumors of embryonic cell origin. |
| Insulin | Insulinoma | They sustained increased insulin levels even in a fasting state. Insulin-producing tumors are typically non-malignant. |
| Parathyroid hormone (PTH) | Liver, renal, breast, lung | Ectopic PTH-producing adenomas are rare but produce PTH in excess, which leads to hypercalcemia. |
| Prolactin | Pituitary, renal, lung | Prolactinomas are common but benign pituitary tumors. Ectopic prolactin-producing carcinomas are sporadic. |
