We have described five different types of tumor MVs and structures with endothelial lining: normal MVs, dilated capillaries (DCs), atypical dilated capillaries (ADCs), structures with partial endothelial lining (cavity structures of type-1), and the distinctive cellular structures in a loose fine-fibered connective tissue of the peritumoral stroma (cavity structures of type-2), in which the DCs with weak expression of CD34 were present. This evidence concerns the gene CD34 and neoplasm.