PECAM1 and neoplasm: Immunohistochemical staining showed the tumor cells were positive for vimentin, but negative for CK, S100, SMA, desmin, myogenin, CD68, STAT6, CD34, CD31, β-catenin, ALK-p80, P53, and MDM2; Ki67 is about 20% in areas of highest activity (Fig. 2).