PECAM1 and neoplasm: The remarkable tumor suppressor capacity of PCNP in vivo was confirmed by IHC analysis for proliferation (Ki67), associated angiogenesis (CD31), apoptosis (cleaved caspase-3), cell cycle (p21), autophagy (Beclin-1) of tumor sections from tumors harvested from control, Mock, PCNP, sh-sub, and sh-PCNP group mice.