NF1 and neuroblastoma: They were able to show not only a clonal evolution from diagnosis to relapse sample but also that 78% (18/23) of the relapsed NB samples harbored a genetic aberration predicted to activate the RAS-MAPK pathway (ALK (10/23); NF1 (2/23); PTPN11 (1/23); FGFR1 (1/23); NRAS (1/23); KRAS (1/23); HRAS (1/23); and BRAF (1/23)) [16].