FLT1 and glioblastoma: The inhibition of proliferation of HUVEC, 4T1 mammary carcinoma cell line that both mostly express VEGFR1 and scarcely VEGFR2, and U87 glioblastoma cell line that highly express VEGFR2 and no VEGFR139–41, further confirmed the dual specificity of VGB4 for VEGFR-1 and -2.