PPM1D and neuroblastoma: Further analysis of PPM1D gene expression in neuroblastoma using the R2 genomics platform of annotated databases (http://r2.amc.nl) demonstrates a correlation of PPM1D mRNA level with higher stage tumors (Fig. 2A) as well as with worse long-term overall survival in a cohort of 88 patients (48% survival versus 78% survival, P < 0.005) (Fig. 2B).