Comparison of the imaging-based EPR measurements to gene expression of VEGF and VEGFR-2.

<p>(a) The 3-day pattern of the enhancement upon injection of the probe to a group of rats (n = 6) indicated a high variability in the tumors leakiness. (b) Relative gene expression of VEGF and VEGFR-2 as measured using qRT-PCR also exhibited a high variability (* indicates p<0.005; data presented as mean±standard deviation). (c–d) The relative gene expression level of each tumor was strongly correlated to its tumor enhancement as imaged by mammography (VEGF-A∶ R² = 0.873, p<0.005; VEGFR-2∶ R² = 0.824, p<0.002). Each animal is assigned the same color in all the graphs (e.g. purple indicates animal number 4).