FN1: A novel fusion partner of ALK in an inflammatory myofibroblastic tumor

Inflammatory myofibroblastic tumors (IMTs) are rare tumors characterized as low-to-intermediate grade sarcomas. Rearrangements of the anaplastic lymphoma kinase (ALK) gene have been reported in IMT. Here, we describe a novel fusion gene in an IMT tumor specimen. A 12-year-old male was admitted to our hospital with a bladder tumor. We identified the fibronectin 1 gene (FN1) as a fusion partner of ALK using 5'RACE. This novel fusion, FN1-ALK, resulted in ALK overexpression in the IMT. This finding should clarify the causes of IMT and facilitate development of novel therapeutics.