t(12;22)(p13;q12) is a rare but recurrent chromosomal abnormality involving the ETS transcription factor ETV6 and meningioma 1 (MN1) genes. In this study, we analyzed the clinical, cytogenetic, and molecular features of five new patients with the t(12;22)/MN1-EVT6 who presented with acute myeloid leukemia or chronic myelomonocytic leukemia. We subsequently reviewed the literature and identified seven additional cases reported with t(12;22)/MN1-EVT6. Our data suggest that neoplasms carrying the t(12;22)/MN1-ETV6, although rare, can commonly present as myeloid neoplasms at the initial diagnosis, including acute myeloid leukemia (n = 8), myelodysplastic syndrome (n = 2), and myelodysplastic/myeloproliferative neoplasms (n = 2). There were five men and seven women with a median age of 43 years (range, 15-63 years) at initial diagnosis. Cytogenetics revealed t(12;22) as the sole abnormality in five patients, with the remaining seven patients harboring additional chromosomal aberrations. Of the five patients who received known therapy regimens, all of them had poor response to the idarubicin/mitoxantrone + cytarabine regimen. Of the seven patients with follow-up information, six patients died with a median overall survival time of only 5 months (range, 1-12 months) after the emergence of t(12;22). In summary, patients with t(12;22) are frequently associated with myeloid neoplasms, poor response to chemotherapy, and inferior outcome.
Keywords: MN1-EVT6 fusion gene; Myeloid neoplasm; t(12;22).