Next generation sequencing of breast implant-associated anaplastic large cell lymphomas reveals a novel STAT3-JAK2 fusion among other activating genetic alterations within the JAK-STAT pathway.

Breast implant associated anaplastic large cell lymphoma (BIA-ALCL) is a distinct type of ALCL, and a new provisional entity by the 2016 revision of the World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues. In contrast to systemic and primary cutaneous ALCLs, BIA-ALCLs have been genetically characterized by the absence of fusions and frequent activation of the JAK-STAT3 pathway through mutations in JAK1 and STAT3. In this study, we report the results of the genetic profiling of 9 BIA-ALCL cases supporting the role of the JAK-STAT pathway activation in this entity, including the identification of an activating STAT3-JAK2 fusion similar to those recently reported in T-cell lymphoproliferative disorders of the gastrointestinal tract. To our knowledge, this is the first fusion reported in BIA-ALCL, providing further insight into the overall genetic landscape of this rare entity as well as uncovering potential options for targeted therapy in cases with advanced disease.