Interestingly, Ki-67 staining showed an 18 fold increase in proliferating cells in areas of neoplasia in Brca2;Trp53 mutants that persisted after castration, compared to control castrated animals (5.5% Ki-67 positive cells vs 0.3% in castrated control) (Figure 5D). The gene discussed is BRCA2; the disease is neoplasm.