Microvascular density, vascular endothelial growth factor immunoreactivity in tumor cells, vessel diameter and intussusceptive microvascular growth in primary melanoma.

Intussusceptive microvascular growth (IMG) corresponds to one of the types of angiogenesis described in literature. Recent morphological work strongly supports a role for IMG, even during tumor angiogenesis. In this study, the extent of angiogenesis, evaluated as microvascular density, the immunoreactivity of tumor cells to vascular endothelial growth factor (VEGF), the vessel diameter and the IMG have been correlated to the tumor thickness in human primary melanoma specimens. Results showed that an increased microvascular density, a strong VEGF immunoreactivity of tumor cells, a major vessel diameter and a high number of connections of intraluminal tissue folds with the opposite vascular wall, expression of IMG, are correlated to a high tumor thickness (>3.6 mm). Overall, these data demonstrate for the first time in human primary melanoma a relationship between angiogenesis, VEGF immunoreactivity of tumor cells, vessels diameter and IMG and seem to indicate that VEGF is specifically involved in increasing vessel diameter and IMG.