The two remaining patients exhibited a more 5' rearrangement at about 10 kb upstream of the MYLbcr region, implying the lack of at least one MYL gene exon in the resulting MYL-RARA fusion gene.     ///    The variation of chromosome breakpoints within the MYL gene may explain size heterogeneity previously observed in some MYL-RARA fusion transcripts expressed in APL cells.. 