Schematic demonstrating the QRT-PCR strategy for detection and quantification of the MLL WT and MLL PTD transcripts in normal karyotype AML and in trisomy 11 AML. The predicted MLL PTD and WT allele-derived transcripts are shown, with the tandemly duplicated exons present in the PTD transcript denoted with gray boxes. Shown above the transcripts are sites for PCR primers (arrows) and fluorogenic probes (rectangles) designed to amplify either the exon 11 to 12 (□), exon 13 to 14 (▧), or exon 26 to 27 (not shown) junctions that are common to the MLL WT and MLL PTD transcripts. Primers and probes (▪) were used to detect the MLL PTD-specific exon 11 to 5 fusion or the exon 12 to 5 fusion found in AML cases with either the MLL PTD of exons 5 through 11 or exons 5 through 12, respectively.