PAS staining combined with endothelial markers (CD31 or CD34) is a commonly used method for identification of tumor VM in paraffin-embedded tissue specimens and was done in 8 studies (66.7%) [41, 42, 45, 50, 52–55], as well as PAS staining in 4 studies [47–49, 51]. This evidence concerns the gene CD34 and neoplasm.