Embryonic vasculogenesis in nodular melanomas and tumour differentiation.

The relationship of vasculogenic mimicry to pigment in nodular vertical growth phase [VGP] cutaneous melanomas is assessed in this study. 10 nodules each from 27 tumors, 15 pigmented and 12 amelanotic were sampled in proportion to the pigment level. Serial frozen and paraffin sections subjected to HE, Reticulin, PAS to assess the vascular pattern; Dopa Oxidase and Immunopositivity for HMB45, LN5 [laminin 5] & integrin[α(5)β(1)], and EM [electron microscopy] to identify Weibel-Palade bodies within endothelial cells.

Patterns of neural differentiation in melanomas.

Background: Melanomas, highly malignant tumors arise from the melanocytes which originate as multipotent neural crest cells during neural tube genesis. The purpose of this study is to assess the pattern of neural differentiation in relation to angiogenesis in VGP melanomas using the tumor as a three dimensional system.

Methods: Tumor-vascular complexes [TVC] are formed at the tumor-stroma interphase, by tumor cells ensheathing angiogenic vessels to proliferate into a mantle of 5 to 6 layers [L1 to L5] forming a perivascular mantle zone [PMZ].