MKI67 and neoplasm: Statistically, when a direct ANOVA was used to compare the differences between the strains, all three assays showed a significant difference among the means (P<0.0001), if one considers that multiple images of the same tumor capture a different ratio of neoplastic:stroma cells as shown in Fig. 3A. However, if a nested one-way ANOVA was performed accounting for multiple measurements, then only differences between these strains were observed in Ki67 staining, suggesting that the strain determines the propensity of proliferation of a neoplastic cell (P=0.0137, F=5.435, DFn=4, Dfd=10).