Angiogenesis and malignant melanoma. Angiogenesis is related to the development of vertical (tumorigenic) growth phase

To study angiogenesis in early steps of melanoma progression, 113 cutaneous melanomas 1mm or less in thickness were stained with Ulex europaeus lectin. Vascular density was determined in the areas of greatest vascularization. To avoid the effect of anatomic location, the quotient between vascular density at the tumor base and in normal skin (vascular ratio) was obtained in each case. Of these melanomas, 46 were immunohistochemically stained for the presence of vascular endothelial growth factor (VEGF). Positivity was scored from 1-4 by comparing staining of melanoma cells with keratinocytes. Vascular ratio values in vertical growth phase melanomas were higher than those in radial growth phase when counting per 200 or 400 magnification (2.29+/-1.3 and 2.48+/-1.5 for vertical growth phase and 1.34+/-0.62 and 1.41+/-0.83 for radial growth phase melanomas, respectively). This difference was statistically significant (p<0.0001 and p<0.001 at x 200 and x 400, respectively). Also, VEGF staining was stronger in vertical growth phase melanomas when compared with radial growth phase melanomas (Chi square, p<0.025). In conclusion, our findings suggest that angiogenesis and VEGF expression are associated with the development of vertical growth phase.