ALBERT

Description: Genetic alterations in the Nucleoporin (NUP) family of genes are involved in myeloid leukemogenesis and are associated with poor prognosis. We previously showed that NUP98-NSD1 is prevalent in acute myeloid leukemia (AML) and is highly associated with FLT3-ITD and dismal outcome. As genetic alterations in the NUP family are frequently cryptic by conventional karyotyping, their incidence has been underestimated. The COG/NCI TARGET AML initiative has performed comprehensive genome-wide characterization of diagnostic specimens from 200 pediatric AML cases in order to identify novel genetic lesions with prognostic and therapeutic significance. The interrogation of the whole genome and RNA sequencing data generated by this initiative identified numerous fusion transcripts involving the NUP family of genes, including NUP98-NSD1, NUP98-KDM5A, NUP98-HOXA9, NUP98-HMG3, NUP98-HOXD13, NUP98-PHF23, NUP98-BRWD3, CLINT-NUP98 and DEK-NUP214. All computationally identified NUP fusions were verified by orthogonal methodology and high-throughput screening assay was developed for frequency determination. The verified NUP fusions were screened in children treated on COG AAML0531 and AAML03P1 to define their prevalence, clinical characteristics and association with clinical outcome. The impact of NUP fusions was initially evaluated in patients with cytogenetically normal AML (CN-AML). NUP fusions were observed in 14.5% (35 of 242) patients: NUP98-NSD1 (N=21), DEK-NUP214 (N=3), NUP98-HMG3 (N=3), NUP98-HOXD13 (N=2), NUP98-PHF23 (N=2) and NUP98-KDM5A (N=4). The NUP fusions NUP98-BRWD3, NUP98-HOXA9 and CLINT-NUP98 were not found in CN-AML patients. Demographics and disease characteristics of CN-AML patients with and without NUP fusions were compared. Although patients of Asian descent comprised only 7% of the study population, they harbored significantly higher number of NUP fusions (29% vs 5%, P =0.002). Among those of Asian descent with CN-AML, 35% harbored a NUP fusion. We also noted an inverse association between NUP fusions and African-Americans where NUP fusions were not identified in any of African-American patients (P =0.031). NUP fusions were correlated with other common mutations in AML. NPM1 (9% vs 28%, P =0.007) and CEBPA (6% vs 19%, P =0.06) were rare in patients with NUP fusions, whereas FLT3/ITD (62% vs 34%, P =0.002) and WT1 (32% vs 8%, P