Specific Tumor markers (Hormones)0

Specific Tumor markers (Hormones)

The production of hormones in cancer involves two separate routs, First there can be an excess production of a hormone by endocrine tissues that are normally produces it , Second , a  hormone may be produced at distant site by a non endocrine tissiue that normally does not produce the hormones . This latter conditions is called ectopic syndrome 

For example the production of adrenocorticotropic hormone (ACTH) by the pituitary gland and by the small cell of the lung exemplifies these two routes .consequently . elevation of the level of a given hormone is not a basis for diagnoses of a specific tumor .

APUDoma 

APUDoma is a group of embryological related tumors of endocrine organs . The acronym (APUD) refers to amine precursor uptake and decarboxylase .APUD cells have properties of both neutral and endocrine tissue. 

These tissue synthesized a number of polypeptide hormones such as ACTH , calcitonin, gastrin , glucagon , insulin,melanosite stimulating hormone , secretin and vasoactive  intestinal polypeptide .

Adrenocorticotropic hormone

ACTH  is a polypeptide hormone with 39 amino acid and molecular weight of 4500 .It produced by corticotropic cells of the anterior pituitary gland .Elevated serum levels of ACTH the result of pituitary or ectopic production . 

A high level of ACTH(>200 ng / L) is of ectopic origin . Failure of the dexamethasone  suppression test is also indicative of ectopic production . About 1/2 of the ectopic production of ACTH is due to the small -cell carcinoma of the lung . Other conditions that elevated ACTH levels : Pancreatic , breast , gastric and colon cancer , as well as benign conditions such chronic obstructive pulmonary disease , mental depression , obesity , hypertension , diabetes mellitus , and stress 

Calcitonin

Calcitonin (CT) is polypeptide . It is formed from 32 Amino acids .Its Molecular weight of 3400 . It is produced by the c-cells of thyroid , Normally , CT is secreted in response to an increase in serum calcium levels . It inhibits the releas of calcium from bone and thus lowers the serum calcium level . The level in health individuals is less than 0.1 micron g /L 

elevated level in medullary carcinoma of the thyroid . In some patient with cancer of the lung , breast , renal , liver and carcinoid  . 

Other non - malignant conditions with CT elevation have been reported such as pulmonary disease , pancreatitis , hyperparathyrodism , pernicious anemia ,paget's disease of bone and pregnancy . 

N.B: 

Calcitonin is most useful in the detection of familial medullary carcinoma of the thyroid , an autosomal dominant disorder . 

Human - chorionic gonadotropin (hCG)

Human - chorionic gonadotropin (hCG) is a glycoprotein. Secreted by the syncytiotrophoblastic cells of normal placenta .

hCG consists of two dissimilar alpha and beta subunits t. The alpha subunits is common to several other hormones,  luteinizing hormone (LH),follicle-stimulating hormone(FSH), the thyroid - stimulating hormone (TSH). The beta subunite is unique to hCG , and the 28 to 30 amino acides comprising the caboxyl terminal are antigenically distinct .hCG has molecular weight of 45000.