FLT1 and cancer: Host VEGFR1 and VEGFR2 mRNA levels were significantly down-regulated following Ad(sh)VEGF and Ad(s)VEGFR2 treatment in SK-N-AS xenografts (p < 0.008 and p < 0.002, respectively), while cancer cell VEGFR1 and VEGFR2 were not significantly different from controls.