PAX5 and B-cell chronic lymphocytic leukemia: Interestingly, in adult chronic lymphocytic leukaemia, the expression of miR-15a/16.1 seems to be regulated by the host gene promoter, which is bound by the transcription factors (TFs) MYC [31] and paired box 5 (PAX5; previously also known as B-cell-specific activator protein, BSAP) [32], while in childhood acute myeloid leukaemia, data from methylation assays indicate that this miRNA cluster is regulated independently of its host gene [33].