Indeed, we could identify a close association of MHCII+/CD31+ cells (vascular leukocytes) with the CD31-positive tumor vasculature, which is restricted to massively infected, late-stage (42 days p.i., Phase III) GLV-1h68-colonized GI-101A tumors (Figure 6a) and not detectable in control tumors (Figure 6b). Here, PECAM1 is linked to neoplasm.