t(3;8)(q26.2;q24) Often Leads to MECOM /MYC Rearrangement and is Commonly Associated with Therapy-Related Myeloid Neoplasms and/or Disease Progression.

t(3;8)(q26.2;q24) is a rare recurrent cytogenetic abnormality that is associated with myeloid neoplasms. We report 20 patients with t(3;8)(q26.2,q24): eight had therapy-related acute myeloid leukemia (AML), three therapy-related myelodysplastic syndrome, four blast phase of chronic myeloid leukemia, one relapsed AML, one AML transformed from chronic myelomonocytic leukemia, one blast phase of an unclassifiable myeloproliferative neoplasm, one de novo myelodysplastic syndrome, and one de novo AML. Nineteen patients presented with cytopenia. Multilineage dysplasia was observed in 16/18 patients, and megakaryocytes were markedly decreased in 11/20 patients. Blasts showed a primitive myeloid immunophenotype in 17 patients, negative for myeloperoxidasein in 14/17 and aberrant CD7 expression in 5/17 patients. Fluorescence in situ hybridization showed MECOM rearrangement in 18/19 and MYC in 16/18 patients. Myc was shown to be expressed in all cases assessed (n=14). Gene mutation testing was performed in 14 patients and seven showed at least one mutation including ASXL1 (2/6), TET2 (2/6), SRSF2 (2/6), and NRAS (2/13). At last clinical follow-up, 18 patients died and two were alive with persistent disease, with a median survival of six months. We conclude that t(3;8)(q26.2;q24) often leads to MECOM and MYC rearrangement, occurs predominantly in therapy-related myeloid neoplasms or at disease progression, and shares some similarities with myeloid neoplasms associated with inv(3)/GATA2-MECOM. Patients with myeloid neoplasms associated with t(3;8)(q26.2;q24) have a dismal outcome.