Yan Xiyun’s group generated a monoclonal antibody, named AA98, specifically against tumor vascular endothelium by the special methodology of differential screening. Using this antibody as a research tool, they discovered a novel marker of tumor vascular endothelium, CD146, and demonstrated that CD146 is specifically over-expressed in nascent vessels and involved in angiogenesis. Animal experiments showed that anti-CD146 antibody, AA98, could inhibit neovascularization and the growth and metastasis of several kinds of tumors.

This work for the first time elucidated the role of CD146in tumor angiogenesis and metastasis and the underlying mechanism. It provided a new target for cancer diagnosis and therapy targeting tumor vessels. Moreover, the antibody AA98 displaying remarked inhibitory activities against angiogenesis and tumor growth has the great potential to be developed as novel anti-cancer therapeutic antibody. This application has attracted the attentions of national and international colleagues and pharmaceutical companies. In 2005 award for the Progress in Science and Technology, Beijing Municipality, had been awarded to this achievement.