Vascular endothelial growth factor (
VEGF) and
vascular endothelial growth factor receptor-2 (VEGFR-2) play a key role in vasculogenesis and angiogenic sprouting, which are crucial for tumour development and
metastasis. In order to determine their possible role in the acquisition of metastatic potential throughout melanocytic tumour progression,
VEGF and
VEGFR-2 immunohistochemical expression were evaluated in 36 human melanocytic tumours of the skin (24
malignant melanomas and 12 common naevi). Different
VEGFR-2 immunostaining patterns were detected in the vast majority of
melanomas (21/24; 88%). A nuclear membrane-like pattern was mainly associated with in situ and microinvasive
melanomas, whereas a combined cytoplasmic membrane and nuclear membrane-like pattern was seen in invasive
melanomas. A nuclear membrane-like pattern was also observed in 83% (10/12) of common naevi. Cytoplasmic immunostaining for
VEGF was observed in 72% (8/11) of in situ/microinvasive
melanomas, 84% (11/13) of invasive
melanomas and 91% (11/12) of naevi. CD31 was also investigated as an immunohistochemical marker for microvessel density (MVD) evaluation. No associations were found between MVD and
VEGF/VEGFR-2 expression. Taken together, these data indicate that
VEGF production is a common event in benign melanocytic tumours, whereas
VEGFR-2 expression, co-localized in the cytoplasmic and nuclear membrane, is associated with progression towards invasive
melanoma. The role exerted by
VEGF/VEGFR-2, however, seems to be independent of the development of a tumour-related capillary network.