FLT1 and neoplasm: Importantly, the present histopathological finding of cleaved caspase 3 also proved that VEGFR1 and 2 peptide vaccination could target wide variety of cells associated with tumor growth, such as vascular endothelial cells, tumor cells, and Foxp3 + Tregs expressing VEGFR1 and/or VEGFR2, which was considered as one of the rationales behind using VEGFRs peptide vaccination with TMZ.