CASP3 and neoplasm: IHC staining of PC3 tumor xenografts treated with anti-Siglec-7/9 mAbs demonstrated higher levels of apoptosis (cleaved caspase 3), decreased proliferation (Ki67), vascularization (CD31), and increased immune cell infiltrates, including CD4+ and CD8+ T cells compared with IgG controls (Figure 5K).