Further, similar to the mECKnull.rK133 tumors, mECrK.219 tumor cells were spindle-shaped in vivo (data not shown), approximately 50% of the tumor cells expressed GFP (Figure 9B), indicating KSHV infection, and the majority of those expressed the pan endothelial marker, CD31/PECAM, on the cell surface (Figure 9B). Here, PECAM1 is linked to neoplasm.