RB1 and neoplasm: Notably, the analysis of the tumors isolated from mice treated for 5 days showed that the inhibition of tumor growth correlated with inhibition of phospho-(Ser780/807/811)-Rb as well as the inhibition of cell cycle progression as indicated by the inhibition of the expression of Topo IIα and phospho-(Ser10)-H3 observed on Western blots (Figure 7D).