 The cytogenetically cryptic t(5;11)(q35;p15) leading to the NUP98-NSD1 fusion is a rare but recurrent gene rearrangement recently reported to identify a group of young AML patients with poor prognosis.     ///    The role of quantitative PCR is also highlighted as a potential tool for managing NUP98-NSD1 positive patients post-treatment..     ///    These data lend support to the adoption of screening for NUP98-NSD1 in pediatric AML without otherwise favorable genetic markers.     ///    NUP98-NSD1 fusion in association with FLT3-ITD mutation identifies a prognostically relevant subgroup of pediatric acute myeloid leukemia patients suitable for monitoring by real time quantitative PCR.. 