PRNP and neuroblastoma: Thus, we measured the relative viability 24 h after treatment with MMS (1 h with 23 h recovery), H2O2 and doxorubicin (both 24 h treatment) in primary PBMCs from both genotypes, and human neuroblastoma cell line SH-SY5Y cells and hu-PrP SH-SY5Y cells, stably expressing moderate (80- to 100-fold, mRNA) higher levels of PrPC than un-transfected SH-SY5Y cells, which express very low levels of PrPC.