UHRF1 and retinoblastoma: Taken together with the P8 retina analysis (Figure 6), the data imply that global hypomethylation driven by high UHRF1 expression is unlikely to be an early event driving retinoblastoma tumorigenesis since there are no significant changes in global methylation among the retinae with different levels of UHRF1 expression and among the retinoblastoma tumors with a different onset time.