e22005 Background: To uncover the genomic characteristics as well as to, within the scope of pediatric soft tissue sarcoma (psts), assess the clinical value of Next Generation Sequencing (NGS), we present the first report of genomic profiles in Chinese psts. Methods: Tumor tissue, as well as peripheral blood from 41 psts patients, were collected in Sun Yat-Sen University Cancer Center, Shenzhen Children's Hospital and Nanfang Hospital. Samples were sequenced in a CLIA/CAP-accredited laboratory with a targeted NGS panel (Onco PanScan plus; GenetronHealth.inc) consisted of all exons of 831 cancer-related genes and mRNA of 395 genes. Bioinformatics analysis was conducted using a build-in computational pipeline. Results: A total of 41 samples consisted of five major histology types including rhabdomyosarcoma (RMS) (n = 11), fibrosarcoma (n = 4), Ewing's sarcoma (n = 4), INI1-deficient mesenchymal tumor (n = 4), and other mesenchymal tumors (n = 18). All patients were with doubtful diagnosis,advanced, relapsed, or refractory sarcoma, of which 85% samples were from initial diagnoses. In totally, we identified 116 somatic aberrations and 4 pathogenic or likely pathogenic germline mutations, with a median tumor mutational burden of 0.47/Mb (0–6.57). Genomic analysis revealed frequent alterations in TP53 (10%), NTRK fusion (10%), PAX3/7 fusion (8%), and ARID1A (7%). ARID1A (18% vs. 0%) and TP53 (18% vs. 3%) mutations were found with higher frequency compared with pediatric RMS data in a previous study (Jack et al 2014). ARID1A mutation was only reported in a RMS case report (Cramer et al 2017). Furthermore, the mutation of ARID1A potentially match PARP inhibitors, which may provide more therapeutic options. In addition, NGS aided pathologic diagnosis in 63% (26/41) patients. The proportion of confirmed diagnosis, differential diagnosis, and the excluded diagnosis was 41.5%, 12.2%, and 9.7%, respectively. Druggable alterations were detected in 39% patients (Table). Four patients received the treatment recommended by genetic testing, three of them with NTRK fusion were recruited in a matched clinical trial could be evaluated and showed partial remission upon Larotrectinib. Conclusions: We discovered ARID1A mutations, which potentially sensitive to PARP-inhibition, were at a higher incidence in Chinese RMS. This study demonstrated the value of NGS test in guiding the clinical practice of psts in Chinese population. [Table: see text]
Next Generation Sequencing Reveals Pathogenic and Actionable Genetic Alterations of Soft Tissue Sarcoma in Chinese Patients: A Single Center Experience
