T(1;21;8)(p34;q22;q22): a novel variant of t(8;21) in acute myeloblastic leukemia with maturation.

The complex variants of t(8;21) involving chromosomes 8 and 21 as well as another chromosome account for approximately 3% of acute myeloid leukemia patients. We report here a 30-year-old male patient with AML-M2. Fluorescence in situ hybridization analysis using dual-color fluorescence ETO and AML1 probes located at 8q22 and 21q22 respectively showed an AML1/ETO fusion signal on the derivative chromosome 8. Whole chromosome painting probes were used for chromosome 1, 8 and 21 and revealed a three-way translocation (1;21;8)(p34 ~ p35;q22;q22). Involvement of chromosome region 1p34 has never been reported earlier, although region 1p35 as a variant in AML with t(8;21) has been reported with an AML1/ETO fusion signal on the 1p35 rather than der(8). In conclusion, combining conventional karyotype, FISH or RT-PCR analyses are a rational strategy for the identification of the complex variants of t(8;21) translocation which could be critical events responsible for leukemogenesis.