SHORT COMMUNICATION B16-F10 melanoma cells contribute to the new formation of blood vessels in the chick embryo chorioallantoic membrane through vasculogenic mimicry Domenico Ribatti • Beatrice Nico • Anca Maria Cimpean • Marius Raica • Enrico Crivellato • Simona Ruggieri • Angelo Vacca Received: 13 December 2011 / Accepted: 3 April 2012 / Published online: 19 April 2012 Ó Springer-Verlag 2012 Abstract 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 mela- noma cell line has been successfully used to study meta- static 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 vas- culogenic mimicry process. Keywords Angiogenesis Á Chorioallantoic membrane Á Melanoma Á Vasculogenic mimicry Introduction Grafting of mammalian cells and tissues to the chick embryo chorioallantoic membrane (CAM) is a well-estab- lished experimental system to evaluate many different parameters of tumor growth [1]. All studies of mammalian neoplasms in the CAM have utilized solid tumors and cell suspensions derived from solid tumors. Tumor explants and tumor cell suspensions invade the chorionic epithelium and form visible masses within 2–5 days after implanta- tion, and tumor cells can be identified in the CAM, as well as in the internal organs of the embryo [1]. B16-F10 murine melanoma cell line has been success- fully used to study metastatic process in the CAM assay. Koop et al. [2, 3] reported a high ratio of cancer cell sur- vival and efficiency of extravasation demonstrating by intravital microscopy that more than 80 % of the B16-F10 cells arrested in the CAM microcirculation, survived and extravasated within 24 h after injection. It is to note that this experimental assay offers the opportunity to study the biologic activities of the B16-F10 cells as in an immunocompromised animal, because the chick embryo is naturally immunodeficient and can accept various cancer cells regardless of their origin without D. Ribatti (&) Á B. Nico Section of Human Anatomy and Histology, Department of Basic Medical Sciences, University of Bari Medical School, Piazza G. Cesare, 11, Policlinico, 70124 Bari, Italy e-mail: ribatti@anatomia.uniba.it A. M. Cimpean Á M. Raica Department of Histology, ‘‘Victor Babes ¸’’ University of Medicine and Pharmacy, Timisoara, Romania E. Crivellato Section of Anatomy, Department of Medical and Morphological Research, University of Udine Medical School, Udine, Italy S. Ruggieri Á A. Vacca Section of Internal Medicine and Clinical Oncology, Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy 123 Clin Exp Med (2013) 13:143–147 DOI 10.1007/s10238-012-0183-8