MKI67 and neoplasm: No significant differences were observed in immunohistochemical detection of phospho-histone H3, a well-established marker for mitosis (Figure 3), cleaved PARP, a marker for apoptosis (Figure 4), or the proliferation marker Ki67 (Figure 5) between control tumours and the two therapeutic regimes: tumours from phenformin pre-treated mice and established tumours treated with phenformin.