FLT1 and glioblastoma: Human gliomas express high levels of VEGFR-1 (Plate et al., 1992); therefore, it was of interest to study whether the VEbp substitutions may alter the MVMp natural tropism to glioblastoma (Rubio et al., 2001; Riolobos et al., 2010; Gil-Ranedo et al., 2021).