Human chorionic gonadotropin (HCG)

Characteristics

HCG is a glykoprotein hormon, 38 kDa, produced in large amounts by placental syncytiotrophoblast cells. It consists of  a specific α-chain and a β-chain common for several polypeptide hormones.

Outside the placenta HCG has been demonstrated in some pituitary cells and in reactive gastrointestinal epithelium.

Neoplasms

HCG is found in moles and choriocarcinoma, chorionic components of germ cell tumours, and syncytiotrophoblast like cells in seminoma/dysgerminoma and embryonal carcinoma.

”Ectopic” HCG may be demonstrated in carcinomas like adenocarcinomas of the gastrointestinal tract, prostate, breast and small cell carcinoma, as well as carcinoid tumour and hepatocellular carcinoma.

Application

Classification of germ cell tumours, identification of extragonadal germ cell tumours.

Visualization

pAbs A0231 and NCL-HCGp are well functioning. Epitope retrieval is recommended, HIER seems to be more effective than proteolyic pre-treatment.

Control tissue: Normal placenta is appropriate. All trophoblastic cells should be strongly stained. The stroma should negative except for a weak reaction in some Hofbauer cells. Note that the HCG expression of the placenta decreases during pregnancy, but should be identified at least until week 32 (unpublished observations).

Assessments

NordiQC Run 11

Selected references

Kovalevskaya G, Genbacev O, Fisher SJ, Caceres E, O'Connor JF. Trophoblast origin of hCG isoforms: cytotrophoblasts are the primary source of choriocarcinoma-like hCG. Mol Cell Endocrinol. 2002 Aug 30;194(1-2):147-55.

Louhimo J, Nordling S, Alfthan H, von Boguslawski K, Stenman UH, Haglund C.  Specific staining of human chorionic gonadotropin beta in benign and malignant gastrointestinal tissues with monoclonal antibodies.
Histopathology. 2001 May;38(5):418-24.

Ozbilim G, Karaburun SP, Zorlu G, Kaya R, Erdogan G, Karaveli S. Immunohistochemical staining properties of PCNA, Ki-67, p53, beta-hCG and HPL in trophoblastic disease. Eur J Gynaecol Oncol. 2000;21(2):200-4.
Losch A, Kainz C. Immunohistochemistry in the diagnosis of the gestational trophoblastic disease. Acta Obstet Gynecol Scand. 1996 Sep;75(8):753-6.

Kido A, Mori M, Adachi Y, Yukaya H, Ishida T, Sugimachi K.  Immunohistochemical expression of beta-human chorionic gonadotropin in colorectal carcinoma. Surg Today. 1996;26(12):966-70.