PECAM1 and neoplasm: Based on the hematoxylin and eosin and IHC staining results of GBM tissues, smaller area of tumor growth, stronger PTEN staining, lower Ki67 proliferative activity, and lower CD31 expression were identified in the shKDELC2 + TMZ group than in the other three groups of mice, which indicated that the combination of KDELC2 knockdown and TMZ chemotherapy effectively inhibited tumor proliferation and angiogenesis of GBM cells (Figure 11C).