Fig. 4

Graphs showing the temporal evolution of tumor volume, viscoelasticity |G*| and phase angle Y are shown for experimental group 2 (a) and group 3 (b). Volumetric analysis of group 2 data showed that tumor volume largely increased in untreated animals over time (A, controls depicted as white dots). In contrast, tumor volume remained almost stable under treatment (A, treated animals depicted as black dots). Viscoelasticity |G*| of the tumor progressively decreased in untreated animals (A, white dots), while it remained almost stable in animals treated with the B20 anti-VEGF-antibody (A, black dots). Similarly, the phase angle Y progressively decreased in untreated tumors (A, white dots). Of note, a decrease of Y is observable in treated animals 10 days after tumor implantation (A, black dots). Lines represent mean and standard deviation. Asterisks indicate the level of significance derived from a two-way ANOVA followed by Bonferroni’s test for multiple comparisons. The effects of anti-angiogenic treatment on established tumors were investigated in a separate experiment (group 3, B). Tumor volume, viscoelasticity |G*| and phase angle Y were compared at baseline (black dots in B), and after 1st (dark grey dots in B) and after 2nd administration (light grey dots in B) of B20 anti-VEGF antibody corresponding to days 8, 10 and 12 after tumor implantation, respectively. Tumor volume did not significantly increase over time. Both viscoelasticity and phase angle decreased over time. Lines represent mean and standard deviation. Asterisks indicate the level of significance derived from a one-way ANOVA followed by Bonferroni’s test for multiple comparisons