Contributed by Deborah Marks, MD and Jeffrey Kant, MD, PhD
Published on line in March 2006
The patient is a 45 year-old male with a past medical history of gastroesophageal reflux disease and hyperlipidemia who presented to his primary care physician with a complaint of increasing fatigue. A routine laboratory assessment was performed and revealed a white blood cell count of 1.4 x 103/ L and platelet count of 108,000/ L. A bone marrow biopsy was performed and was consistent with acute myeloid leukemia (see figure 1). A reverse transcriptase polymerase chain reaction (RT-PCR) was performed on the patient's peripheral blood (see figure 2).
Figure 1. Representative image of peripheral blood. Promyelocytes containing multiple Auer rods.
Figure 2. Gel electrophoretic analysis of RT-PCR for the PML-RARA translocation. Reverse transcription and nested PCR amplification was performed using primers from exon 6 of the PML gene and exon 3 of the RARA gene (intron 6 breakpoint anaylsis) in two separate reactions. PBGD = porphobilinogen deaminase, a housekeeping gene.
The gel reveals a band of approximately 220 base pairs at two different RNA concentrations in the intron 6 breakpoint analysis. There are also alternatively-spliced bands in the intron 3 breakpoint analysis. Based on a combination of bone marrow and peripheral blood findings, including the RT-PCR analysis shown above, a diagnosis was rendered.