As shown in Fig.2, in control group, hematoxylin and eosin (H&E) staining showed VM channels formed by tumor cells and erythrocytes at the center of the channels; CD31-PAS double staining showed CD31-negative PAS-positive substances lining channels and forming basement membrane-like structures (VM) with single erythrocyte inside (Fig.2A and 2B). The gene discussed is PECAM1; the disease is neoplasm.