 The ProALL prototype assay microRNAs miRNAs Avigad et al., 2016 were discovered by microarray analysis by hybridization of BM aspirates taken at diagnosis of 48 ALL patients to 979 different miRNAs. The down-regulated expression levels of miR-451 and miR-151-5p and the up-regulated expression level of miR-1290 associated with adverse prognostic factors. 