RNA-sequencing of acute promyelocytic leukemia primary blasts reveals novel molecular biomarkers of early death events.

Although acute promyelocytic leukemia (APL) has evolved to the AML entity with the best prognosis, typical 'early death' (ED) events still account for mortality rates of ∼20% in population-based studies. To investigate this poorly understood issue we performed whole transcriptome analysis of n = 7 APL ED cases compared to n = 7 APL cases with long term remission. We discovered the proteins S100A8/S100A9 and EFEMP1 as the most differentially expressed factors. In an independent cohort of n = 58 APL patients EFEMP1 over-expression was associated with a worse overall survival. Furthermore, a subgroup analysis of ED caused by hemorrhagic complications revealed an association of metallothioneins (MT1G/MT1E) with higher bleeding rates, ED events and negative prognostic effects on overall survival. Finally, we identified a novel TPM4-KLF2 fusion transcripts in 44/64 APL samples. In summary, we report a comprehensive transcriptomic analysis and novel potential biomarkers of ED biology, which highlight novel pathways in ED events in APL.