Alveolar Soft Part Sarcoma Chromosome Region, Candidate 1 (ASPSCR1)

ASPSCR1 is fused with transcription factor TFE3 gene in ASPS and also in renal cell carcinomas. Several alternatively spliced transcript variants of this gene have been described, but their full length nature has not been determined. By amplification of the 5-prime portion of cDNAs containing the 3-prime portion of TFE3 in 2 ASPS cases, they identified a novel sequence, ASPSCR1 (designated ASPL by the authors), fused in-frame to TFE3 exon 4 or exon 3. RT-PCR analysis detected an ASPSCR1/TFE3 fusion transcript in all 12 ASPS cases studied. The ASPSCR1/TFE3 fusion replaces the N-terminal portion of TFE3 by the fused ASPSCR1 sequences, while retaining the TFE3 DNA-binding domain, implicating transcriptional deregulation in the pathogenesis of ASPS.