| Abstract: | Acute leukaemia in early childhood ‐ and mainly infant leukaemia (IL) – is characterized by acquired genetic alterations, most commonly by the presence of distinct MLL rearrangements (MLL‐r). The aim of this study was to investigate possible correlations between clinical features and molecular analyses of a series of 545 childhood leukaemia (≤24 months of age) cases: 385 acute lymphoblastic leukaemia (ALL) and 160 acute myeloid leukaemia (AML). The location of the genomic breakpoints was determined in a subset of 30 MLL‐r cases. The overall survival of the investigated cohort was 60·5%, as determined by the Kaplan‐Meier method. Worse outcomes were associated with age at diagnosis ≤6 months (P < 0·001), high white blood cell count (P = 0·001), and MLL‐r (P = 0·002) in ALL, while children with AML displayed a poorer outcome (P = 0·009) regardless of their age strata. Moreover, we present first evidence that MLL‐r patients with poor outcome preferentially displayed chromosomal breakpoints within MLL intron 11. Based on the literature, most MLL‐r IL display a breakpoint localization towards intron 11, which in turn may explain their worse clinical course. In summary, the MLL breakpoint localization is of clinical importance and should be considered as a novel outcome predictor for MLL‐r patients. |
