beta-HCG(beta-Human Chorionic Gonadotropin), also termed as Chorionic Gonadotropin, Beta Chain(CGB). It is encoded by a multigene cluster composed of six homologous sequences. And in the family of beta-containing glycoprotein hormones, beta-HCG is unique in that it contains an extension of 29 amino acids at its COOH end. beta-HCG is mapped to 19q13.32 and expressed in trophoblast and various malignant tumors promotes cellular motility in vivo. beta-HCG has a novel function in uterine adaptation to early pregnancy as well as in tumor development and underline the importance of HCG as an as yet unrecognized angiogenic factor.