Beta HCG-human chorionioc gonadotrophin.

Human  Chorionic  Gonadotropin as marker!!! Hcg is a glycoprotein composed of two dissimilar subunits alpha and beta subunits. The alpha subunits of hcg, FSH, LH and TSH are nearly identical but the beta subunit is unique in its immunological and biological properties . Patients with gestational trophoblastic disease produce concentration of hcg equal to or exceeding levels produced in normal pregnancy for similar gestational age. The level of hcg fails to plateau at the end of the first trimester in these cases and continues to rise in proportion to in increase in trophoblastic cell mass. Thus beta hcg levels are useful for diagnosing GTD . After evacuation of the uterus quantitative beta hcg titers for one year. If hcg titers plateau or rise indicating persistent GTD a further clinical workup is necessary to rule out metastatic disease. The ratio  of free beta subunit of hcg to total hcg is valuable in the evaluation of GTD. The free beta hcg/ total hcg ratio is higher in GTD than in normal pregnancies. This ratio is lowest in Patients with hydatiform mole intermediate in invasive mole and highest in choriocarcinoma.

Beta hcg titers are extremely useful in the diagnosis and treatment of testicular tumours. They contribute greatly to the diagnosis immunohistochemical classification ,staging and follow- up of these tumours. About 50-90% cases with nonseminomatous tumours show elevated levels f beta hcg . this test is used in the evaluation of testicular masses in the staging of testicular germ cell tumours and in monitoring the response to therapy. Plasma levels of beta hcg are elevated in all patients with choriocarcinoma one third patients of embryonal carcinomas and teratocarcinomas and rarely in seminomas. Patients with seminoma and elevated beta hcg have a less favourable prognosis than those with seminoma with normal beta hcg titers . False positive results occur in men with solitary testis.

Beta hCg can serve as tumour marker for various ovarian germ cell tumours like choriocarcinoma endodermal sinus tumour embronal carcinoma nd dysgerminoma . Serial quantitative beta hCG concentrations are helpful in monitoring patients for evidence of persistence or recurrence after chemotherapy or surgery.