Fig. 5

Histology satellite study. a No major differences in pimonidazole staining were observed between the different therapies at the different points in time. b Representative pimonidazole-stained tumor tissue of a metformin (MET)-treated animal. The arrow indicates a hypoxic area. c Same conclusions could be drawn for the Ki67 staining. d Representative Ki67-stained tumor tissue of a metformin-treated animal. Arrows indicate Ki67-positively staining nuclei. e 48 h post-therapy, the cleaved caspase-3 (CC3)-positive fraction was significantly increased in combination-treated tumors as compared to control. f Representative CC3-stained tumor tissue of a metformin-treated animal. Arrows indicate CC3-positively staining apoptotic fragments. **, p < 0.001; base, baseline; RT, radiotherapy