A new four-way complex translocation variant involving the t(8;5;21;4)(q21;q13,q22,q31) and the relocalization of AML1/ETO fusion gene.

In acute myeloid leukemia, t(8;21) detected with a frequency of 10% is associated with good prognosis. However, variant t(8;21) is observed in 4% of these cases, and although the prognostic effects of these variant translocations have not been clearly revealed, there are findings that they affect the prognosis poorly. Here, we report on a 39 years old man, detected 4-way varyant t(8;21) which include relocalization of RUNX1/RUNX1T1 fusion gene, and loss of Y chromosome. RT-PCR also confirmed RUNX1/RUNX1T1 fusion transcript. Additionally, D820G and N822K mutations on KIT gene and mut B on NMP1 gene were detected. A complete remission could not achieved after first chemotherapy treatment. Due to primary resistance and variant of t(8;21), stem cell transplantation was performed. The variant translocation we have reported is unique and also the case is the second case that was reported in the literature in terms of the relocation of the AML1/ETO fusion gene. Since c-KIT mutations and LOY were also observed, it is not possible to predict the prognosis. To highlight the importance of variant translocations and relocalization of fusion gene, more cytogenetic and molecular data are needed.