B16-F10 melanoma cells contribute to the new formation of blood vessels in the chick embryo chorioallantoic membrane through vasculogenic mimicry.

Grafting of mammalian cells and tissues to the chick embryo chorioallantoic membrane (CAM) is a well-established experimental system to evaluate many different parameters of tumor growth, and B16-F10 murine melanoma cell line has been successfully used to study metastatic process in the CAM assay. The aim of this study was to demonstrate the capability of B16-F10 melanoma cells to contribute to the new formation of host blood vessels through a vasculogenic mimicry mode. Results have shown that B16-F10 melanoma cells are able to form in 4 days macroscopic tumor masses and induce a strong angiogenic response comparable to that of a well-known angiogenic cytokine, namely fibroblast growth factor-2. Moreover, tumor cells are able to cross the chorionic epithelium, and to move beneath in the mesenchyme to form tumor masses immunoreactive to specific antibodies anti-S100 and anti-MART-1/Melan-A. Finally, we have shown that CAMs new-formed blood vessels are lined by both pigmented melanoma cells and cells immunoreactive to MART-1/Melan-A and PAS, suggesting the occurrence of a vasculogenic mimicry process.