The prognostic significance of microvessel density (MVD) in cutaneous melanoma is controversial according to conducted relevant studies. The aim of our study was to reveal the possible correlation between immunohistochemical indicators of proliferation and MVD investigating Ki-67, PECAM-1 and EGFR in cutaneous melanocytic neoplasia Materials and Methods: The study enrolled 33 patients with cutaneous melanocytic neoplasia (18 patients with benign, including 6 atypical nevus and 15 patients with

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... align neoplasia) retrospectively. The immunohistochemical examination has been performed on paraffin-embedded sections of melanocytic neoplasia's tissue (dysplastic nevi and melanoma) using monoclonal antibodies against Ki-67, VEGF and CD31/PECAM-1. Results: Moderate proliferative activity was seen in 10 malign melanoma cases (66.7%) and in 4 cases (22.2%) of benign melanocytic neoplasia. It should be noted that the all the latter cases were in dysplastic nevi subgroup. Low neoplastic activity was seen only in other 14 cases (77.8%) of benign melanocytic nevi (p < 0.01). VEGF-expression was positive in all melanoma cases and in 2 cases of benign melanocytic nevi (p < 0.001). MVD was significantly different in melanoma and benign melanocytic nevi cases (p < 0.01). A direct strong correlation between Ki-67 expression and MVD in cutaneous melanocytic neoplasia was found (r = +0.78). Conclusion: High PECAM-1 expression in cutaneous melanocytic neoplasia, that is a surrogate marker of tumor neoangiogenesis, is correlated with higher proliferative activity of melanocytic cells. Such tumors theoretically can have higher metastatic potential not only due to high proliferative activity of melanoma cells also because of having abundant microvessels that are essential for making contact between malignant cells and bloodstream for developing hematogenic metastasis. Further investigations are needed to clarify the prognostic significance of PECAM-1 expression skin melanoma tissue.