CASP3 and cancer: “Normalized” vessels were identified using several tests [35]: α-SMA and CD31 staining was used to identify pericytes-covered tumor vessels; pimonidazole (PIMO) staining was conducted to visualize hypoxic regions in tumors; caspase-3 staining was used to identify cancer cells that underwent apoptosis during vasculature “normalization”; FITC-conjugated lectin was used to study perfusion (Fig 9).