Complex karyotype newly defined: the strongest prognostic factor in advanced childhood myelodysplastic syndrome

To identify cytogenetic risk factors predicting outcome in children with advanced myelodysplastic syndrome, overall survival of 192 children prospectively enrolled in European Working Group of Myelodysplastic Syndrome in Childhood studies was evaluated with regard to karyotypic complexity. Structurally complex constitutes a new definition of complex karyotype characterized by more than or equal to 3 chromosomal aberrations, including at least one structural aberration. Five-year overall survival in patients with more than or equal to 3 clonal aberrations, which were not structurally complex, did not differ from that observed in patients with normal karyotype. Cox regression analysis revealed the presence of a monosomal and structurally complex karyotype to be strongly associated with poor prognosis (hazard ratio = 4.6, P < .01). Notably, a structurally complex karyotype without a monosomy was associated with a very short 2-year overall survival probability of only 14% (hazard ratio = 14.5; P < .01). The presence of a structurally complex karyotype was the strongest independent prognostic marker predicting poor outcome in children with advanced myelodysplastic syndrome

Pediatric acute myeloid leukemia with t(8;16)(p11;p13), a distinct clinical and biological entity: A collaborative study by the International-Berlin- Frankfurt-Münster AML-study group

In pediatric acute myeloid leukemia (AML), cytogenetic abnormalities are strong indicators of prognosis. Some recurrent cytogenetic abnormalities, such as t(8;16)(p11;p13), are so rare that collaborative studies are required to define their prognostic impact. We collected the clinical characteristics, morphology, and immunophenotypes of 62 pediatric AML patients with t(8;16)(p11;p13) from 18 countries participating in the International Berlin-Frankfurt-Münster (I-BFM) AML study group. We used the AML-BFM cohort diagnosed from 1995-2005 (n = 543) as a reference cohort. Median age of the pediatric t(8;16)(p11;p13) AML patients was significantly lower (1.2 years). The majority (97%) had M4-M5 French-American-British type, significantly different from the reference cohort. Erythrophagocytosis (70%), leukemia cutis (58%), and disseminated intravascular coagulation (39%) occurred frequently. Strikingly, spontaneous remissions occurred in 7 neonates with t(8;16)(p11;p13), of whom 3 remain in continuous remission. The 5-year overall survival of patients diagnosed after 1993 was 59%, similar to the reference cohort (P =.14). Gene expression profiles of t(8;16) (p11;p13) pediatric AML cases clustered close to, but distinct from, MLL-rearranged AML. Highly expressed genes included HOXA11, HOXA10, RET, PERP, and GGA2. In conclusion, pediatric t(8;16)(p11;p13) AML is a rare entity defined by a unique gene expression signature and distinct clinical features in whom spontaneous remissions occur in a subset of neonatal cases