NAB2STAT6

NAB2STAT6 is a gene fusion between NAB2 and STAT6, most commonly arising from the chromosomal translocation t(12;18)(q13;q11) and is a defining molecular feature of solitary fibrous tumor (SFT). SFTs are rare mesenchymal neoplasms that can occur in various locations, including the pleura, meninges, and soft tissues.

Molecularly, the NAB2-STAT6 fusion creates a chimeric transcription factor that disrupts normal transcriptional control and alters gene expression to promote tumor development. Multiple fusion variants have been described, involving different exons of NAB2 fused to STAT6; these variants may correlate with histologic patterns, though their impact on prognosis is not fully established.

Diagnosis relies on both morphology and immunohistochemistry. The fusion leads to strong, diffuse nuclear staining for STAT6 by IHC, a highly sensitive and specific marker for SFT. Molecular confirmation can be obtained by RNA sequencing or targeted FISH/RT-PCR to detect NAB2-STAT6.

Clinical management: Treatment is primarily surgical excision. SFTs generally behave in a slow-growing fashion but can recur or metastasize, especially when atypical features are present. The presence of NAB2-STAT6 fusion is a characteristic feature aiding diagnosis; it is not, by itself, a definitive predictor of outcome, though ongoing research explores possible associations with tumor behavior.