Cancer Biology

Angiogenesis is the process of formation of new blood vessels from pre-existing vessels or endothelial cell progenitors. It plays a crucial role in tumor growth and metastasis. Tumor angiogenesis have been widely studied as an important target for suppressing tumor growth and metastasis. Here, we describe an in vivo chick embryo chorioallantoic membrane (CAM) model. The chick embryo chorioallantoic membrane is an extraembryonic and is rich of blood vessels. After exposing the vascular zone of the CAM, a sterilized filter-paper disk is employed, which is used as a carrier for being loaded with various chemicals, drugs or virus. Finally, the CAM was fixed and spread on glass slide, and the blood vessels were quantified by counting the number of blood vessel branch points. Compared with the matrigel plug angiogenesis assay, in which tumor cells are mixed with the matrigel gel (expensive) and injected into the mice, subsequently using immunohistochemistry (IHC) staining (time consuming) with the endothelial marker to indicate the presence of the newly formed capillaries, the main advantages of CAM model are its low cost, simplicity, reproducibility, and reliability. Thus, the CAM can be widely used in vivo to study both angiogenesis and anti-angiogenesis.