Case Report: Myeloid neoplasms with the t(3;12)(q26.2;p13.1)/MECOM-ETV6 translocation: report of two new cases and review of the literature

The <i>MECOM</i> (<i>MDS1</i> and <i>EVI1</i> complex locus) gene, located at 3q26.2, encodes an oncogenic transcription factor implicated in multiple signaling pathways. Rearrangements involving <i>MECOM</i>/3q26.2, including inversions, translocations, insertions and cryptic chromosomal changes, are observed in myeloid neoplasms and are associated with high-risk disease features and poor clinical outcomes. The translocation t(3;12)(q26.2;p13.1) is a rare genetic event, resulting in a fusion of the <i>MECOM</i> gene at 3q26.2 with the <i>ETV6</i> gene at 12p13.1. To date, only 78 cases of hematologic neoplasms harboring t(3;12) have been reported in the English literature, primarily as case reports or case series. T(3;12) has been associated with abnormalities of chromosome 7, multiple hematopoietic lineage dysplasia, and poor prognosis. Given its rarity, studies on t(3;12) in myeloid neoplasms are limited. In this report, we present two additional cases exhibiting t(3;12), initially identified through routine karyotyping. The clinicopathological, cytogenetic and molecular genetic characteristics were summarized and discussed. A comprehensive review of partner genomic loci and genes mutated in myeloid neoplasms with <i>MECOM</i> rearrangement was conducted. The <i>AF4</i> gene and the transcription elongation control pathways are proposed as potential therapeutic targets for <i>MECOM</i>-rearranged myeloid neoplasms.