ISG15 as a prognostic biomarker in solitary fibrous tumour

Background: Solitary fibrous tumour (SFT) is a rare mesenchymal malignancy that lacks robust prognostic and predictive biomarkers. Interferon-stimulated gene 15 (ISG15) ubiquitin-like modifier, associated with progression, poor survival of SFT patients, as previous published by our group. Here, we describe the role ISG15 in biology this tumour. Materials methods: expression was assessed immunohistochemistry tissue microarrays from patients tested for correlation progression-free overall (OS). The effects knockdown or induction were investigated cancer stem cell (CSC) characteristics drug sensitivity unique vitro models SFT. Results: value OS validated at protein level malignant prospectively treated pazopanib enrolled GEIS-32 trial. In models, lead to decrease CSC-related genes, including SOX2, NANOG, ALDH1A1, ABCB1 ABCC1. Likewise, downregulation decreased clonogenic/ tumoursphere-forming ability cells, while enhancing apoptotic death after doxorubicin, trabectedin treatment 3D cultures. regulation genes confirmed inducing its interferon-β1; upregulated 1.28- 451-fold CSC-associated genes. Conclusions: factor SFT, regulating CSCs maintenance. Our results suggest could be novel therapeutic target which improve efficacy currently available treatments. Conflict interest: Other Substantive Relationships: D.S.M. reports institutional research grants PharmaMar, Eisai, Immix BioPharma Novartis outside submitted work travel support Celgene, Bayer Pfizer. NH grants, personal fees non-support re-search funding clinical studies (institutional) Eli Lilly Company, AROG, Bayer, Lixte, Karyopharm, Deciphera, GSK, Novartis, Blueprint, Nektar, Forma, Amgen Daichii-Sankyo. J.M.-B. honoraria advisory board participation expert testimony Eisai All other authors declare there no conflict interest.