MKI67 and breast neoplasm: Following MC2494 treatment, a block of proliferation Proliferating cell nuclear antigen [PCNA] and Ki67 and an induction of cell death (PARP and RIPK1) were observed after immunohistochemistry analysis performed on murine breast tumor specimens derived from allograft BALB/c mice (Figure 6), supporting the data obtained in cell lines and extending previous results [28].