Abstract 3029
Background
About half of ESS do not harbor a JAZF1 or YWHAE fusion and other rearrangements have already been reported. With the aim to provide a comprehensive description of the molecular landscape of endometrial stromal sarcomas (ESS), we investigated by RNA-sequencing a series of tumors diagnosed as ESS based on the morphology but negative for JAZF1 and/or YWHAE in FISH experiments.
Methods
This study was performed between September 2017 and December 2018 as a Centre Léon Bérard monocentric retrospective translational research program on tumor samples from an investigational cohort of 43 ESS patients. For clustering analyses, we used a control cohort composed of 19 patient samples of BCOR-rearranged sarcomas (n = 8), low-grade ESS with JAZF1-SUZ12 fusion (n = 5), high-grade ESS carrying a BCOR internal tandem duplication (n = 1), uterine leiomyoma (n = 2) and uterine leiomyosarcomas (n = 3). RNA sequencing was performed from FFPE material in all cases using TruSeq RNA Access Library Prep Kit (Illumina®).
Results
A chromosomal rearrangement was identified in 74% of the cases (n = 32). We identified biologically homogeneous groups of tumors such as the JAZF1-fused (to PHF1 and SYNGAP1) and the BCOR-rearranged (BCOR-ITD, ZC3H7B-BCOR, CREBBP-BCOR). Using a clustering approach on transcriptomic data, tumors were divided in 3 subgroups: one mainly composed of BCOR-rearranged ESS (n = 7), one mainly composed of JAZF1-fused ESS (n = 14) and one composed of various molecular subtypes (n = 22). This 3 subgroups display significantly different survivals (Log-rank test, p = 0.004). Five cases which harbored a YWAHE-NUTM2B fusions clustered separately: 3 cases in the group of indolent tumors (JAZF1-fused ESS) and 2 cases in the group of aggressive tumors (BCOR-rearranged sarcomas). Of note, those 2 cases harbored also a single nucleotide variant, one on BCOR and one on BCORL1. Results of RNA-seq and clustering analysis have allowed a better classification in 6 cases.
Conclusions
This is the largest series of RNAseq performed in a very rare subtype of tumors: ESS. We report new and recurrent molecular variants of ESS including previously unreported fusions. RNA-sequencing may support the diagnosis of ESS and help a better classification.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
InterSARC grants.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4210 - Efficacy and safety of apatinib for advanced gastrointestinal stromal tumors after failure of imatinib and sunitinib: An open-label, multicenter, single-arm, phase II trial
Presenter: Zhaolun Cai
Session: Poster Display session 1
Resources:
Abstract
4526 - Long-term outcome of neoadjuvant tyrosine kinase inhibitors (TKI) in locally advanced dermatofibrosarcoma protuberans (DFSP)
Presenter: Jessica Beaziz
Session: Poster Display session 1
Resources:
Abstract
1214 - Neo-adjuvant (NA) Imatinib for gastrointestinal stromal tumours (GISTs): What is the optimal length of treatment?
Presenter: Tom Wilson
Session: Poster Display session 1
Resources:
Abstract
2690 - Gastrointestinal Stromal Tumours (GIST) in adolescents and young adults (AYA)
Presenter: Nikki Ijzerman
Session: Poster Display session 1
Resources:
Abstract
4558 - Radiomics improves response evaluation for desmoid tumors treated with chemotherapy
Presenter: Amandine Crombe
Session: Poster Display session 1
Resources:
Abstract
2751 - Radiomics of gastrointestinal stromal tumors; risk classification based on computed tomography images – a pilot study
Presenter: Milea Timbergen
Session: Poster Display session 1
Resources:
Abstract
2737 - Differentiating well-differentiated liposarcomas from lipomas using a radiomics approach
Presenter: Melissa Vos
Session: Poster Display session 1
Resources:
Abstract
1282 - The immune landscape of chondrosarcoma reveals an anti inflammatory environment
Presenter: Iseulys Richert
Session: Poster Display session 1
Resources:
Abstract
1572 - Impact of Immunotherapy and Targeted Therapy on Tumor Growth Rate in Sarcoma
Presenter: Esmail Al-ezzi
Session: Poster Display session 1
Resources:
Abstract
3414 - DNA methylation profiles of angiosarcoma subtypes.
Presenter: Marije Weidema
Session: Poster Display session 1
Resources:
Abstract