Fusion of the genes ataxin 2 like, ATXN2L, and Janus kinase 2, JAK2, in cutaneous CD4 positive T-cell lymphoma

Acquired mutations were recently described in cutaneous T-cell lymphomas for the JAK1, JAK3, STAT3, and STAT5B genes of the JAK-STAT pathway. In the present study, RNA-sequencing of a primary cutaneous CD4 positive T-cell lymphoma carrying a three-way t(9;13;16)(p24;q34;p11) chromosome translocation showed that JAK2 from chromosome band 9p24 was rearranged and fused to a novel partner gene, ATXN2L, from 16p11. RT-PCR together with Sanger sequencing verified the presence of the ATXN2L-JAK2 fusion transcript. The ATXN2L-JAK2 fusion gene would code for a chimeric protein containing all domains of ATXN2L and the catalytic domain of the JAK2 tyrosine kinase. The ATXN2L-JAK2 chimeric protein could lead to constitutive activation of the downstream JAK-STAT signaling pathway in a manner similar to that seen for other JAK2 fusion proteins.