t(8;21;8)(p23;q22;q22): A New Variant form of t(8;21) Translocation in Acute Myeloblastic Leukemia with Maturation

Abstract

The complex variants of t(8;21) involving chromosomes 8 and 21 as well as a variable chromosome account for 1.1 ∼5% of acute myeloid leukemia (AML) patients. This paper reports a case of AML-M2 with t(8;21;8) translocation for the first time. The patient was a female, aged 47 years. Her myelogram was compatible with AML-M2. Chromosome study using R-banding technique revealed a karyotype 46, XX, t(8;8)(p23;q22). Dual-color FISH assay with two probes P1 164(green signal) and YAC 225B8 (red signal) both of which closely located on the 8q showed that one yellow signal consisting of a green signal and a red signal and one red signal appeared on the long and the short arm of the same der(8) chromosome, respectively, further confirming this translocation occurred between both homologous chromosomes 8. RT-PCR analysis detected the AML1/ETO fusion transcript in our patient, thus indicating that this chromosomal aberration was, in fact, a complex three-way rearrangement t(8;21;8)(p23;q22;q22). In conclusion, combining conventional karyotype, FISH or RT-PCR analyses is a rational strategy for identification of the complex variants of t(8;21) translocation.

Key Words:

• acute myeloid leukemia with maturation
• 8;21 translocation
• variant translocation
• fluorescence in situ hybridization
• Reverse transcription polymerase chain reaction