Histological analysis with IHC staining in 4T1 tumors in response to KGP265. (A) H&E staining showed differences between the control and KGP265 treated 4T1 tumor tissues. (B) IHC images of 4T1 tumor tissue sections, and graphs showing the levels of pimonidazole in the control and KGP265 treated tumors. (C) Representative IHC images of 4T1 tumor tissue sections, and graphs showing the levels of Ki67 in the control and KGP265-treated tumors. The red rectangles in the montages show expanded regions in 40× images. Scale bar: montage, 2 mm; 40×, 50 µm. The staining levels were quantified, and the data were plotted as the mean ± SEM. The values shown in the graphs are averages of the signals quantified from three independent tumors in the IHC experiments. For the statistical analysis, the levels in the treated tumors were compared to the levels in the control tumors with an unpaired t-test. * p < 0.05, ** p < 0.01 and *** p < 0.001.