Translocations involving nucleoporin 98kD (NUP98) on chromosome 11p15 occur at relatively low frequency in acute myeloid leukemia (AML) but can be missed with routine karyotyping. In this study, high-resolution genome-wide copy number analyses revealed cryptic NUP98/ NSD1 translocations in 3 of 92 cytogenetically normal (CN)-AML cases. To determine their exact frequency, we screened > 1000 well-characterized pediatric and adult AML cases using a NUP98/NSD1-specific RT-PCR. Twenty-three cases harbored the NUP98/NSD1 fusion, representing 16.1% of pediatric and 2.3% of adult CN-AML patients. NUP98/NSD1-positive AML cases had significantly higher white blood cell counts (median, 147 ؋ 10 9 /L), more frequent FAB-M4/M5 morphology (in 63%), and more CN-AML (in 78%), FLT3/internal tandem duplication (in 91%) and WT1 mutations (in 45%) than NUP98/ NSD1-negative cases. NUP98/NSD1 was mutually exclusive with all recurrent type-II aberrations. Importantly, NUP98/ NSD1 was an independent predictor for poor prognosis; 4-year event-free survival was < 10% for both pediatric and adult NUP98/NSD1-positive AML patients. NUP98/NSD1-positive AML showed a characteristic HOX-gene expression pattern, distinct from, for example, MLLrearranged AML, and the fusion protein was aberrantly localized in nuclear aggregates, providing insight into the leukemogenic pathways of these AMLs. Taken together, NUP98/NSD1 identifies a previously unrecognized group of young AML patients, with distinct characteristics and dismal prognosis, for whom new treatment strategies are urgently needed. (Blood. 2011;118(13):3645-3656)

Key Points Patients with PMF may carry JAK2 (V617F), a CALR exon 9 indel, an MPL exon 10 mutation, or none of these genetic lesions. The genetic subtypes of PMF differ substantially as regards clinical course, disease progression, and overall survival.

The prevalence, the prognostic effect, and interaction with other molecular markers of DNMT3A mutations was studied in 415 patients with acute myeloid leukemia (AML) younger than 60 years. We show mutations in DNMT3A