Recurrent JAZF1 rearrangements have been reported to be most frequent in low-grade stromal sarcomas (up to 60%), while YWHAE rearrangements are characteristic of high-grade ESS.
In an update based on the 2014 WHO classification, low-grade ESS is often associated with gene rearrangement bringing about the JAZF 1-SUZ12 (formerly JAZF1-JJAZ1) fusion gene, whereas high-grade ESS is associated with the YWHAE-NUTM fusion gene.
We applied an NGS-based fusion transcript detection assay (Archer FusionPlex Sarcoma Panel) that targets YWHAE and JAZF1 fusions in a series of low-grade ESSs (n = 11) and high-grade ESSs (n = 5) that were previously confirmed to harbour genetic rearrangements by fluorescence in-situ hybridization (FISH) and/or reverse transcription polymerase chain reaction (RT-PCR) analyses.
Thirteen (81.3%) of 16 LGESSs with interpretable results showed JAZF1 and/or PHF1 genetic rearrangements by fluorescence in situ hybridization, and the only HGESS in the series showed YWHAE genetic rearrangement.
These findings show that this reverse transcription-polymerase chain reaction assay is sensitive and specific for detection of YWHAE-FAM22 fusion transcript and can serve as a useful adjunct diagnostic assay to confirm the diagnosis of YWHAE-FAM22 endometrial stromal sarcoma in formalin-fixed and paraffin-embedded tumor samples.