PECAM1 and neoplasm: In vivo, the synergistic anti-glioma action of CBD and THC was further confirmed in a subcutaneous tumor xenograft model in athymic nude mice using U-87MG cells, demonstrated by anti-tumor cell proliferation (identified by Ki-67), induction of apoptosis (identified by TUNEL), and anti-tumor angiogenesis (identified by CD31 immunostaining) [48].