Identification of novel actionable SNVs using targeted comprehensive genome profiling in patients with sarcoma

e23520 Background: The utility of comprehensive genome profiling is not well validated in early-stage sarcoma. The 5-year survival rate for metastatic sarcoma is less than 20%. The application of comprehensive Next Generation Sequencing (NGS) on tumor DNA has led to the identification of a multitude of actionable alterations in oncogenes & tumor suppressor genes alongside the detection of immunotherapy markers like microsatellite instability, tumor mutational burden, and homologous recombinant deficiency. Methods: We retrospectively analyzed ccfDNA and gDNA in 13 sarcoma patients by targeted Next Generation Sequencing (NGS) using OncoIndx proprietary gene panel that targets exonic regions of 600 cancer-related genes. Illumina-compatible libraries were prepared by the target hybridization method and sequenced on Nextseq 2000 platform in a pair-end fashion. Variant calling was performed using an indigenously developed bioinformatics pipeline. Results: Here we report for the first time the identification of several, novel mutations in rare sarcomas such as IDH2R140W (in epithelioid hemangioendothelioma), CTNNB1D32V (in undifferentiated small round cell sarcoma) and DDR2M754I (in osteosarcoma). Furthermore, we observed, JAK1 amplification and BRAF-GUSBP1 fusion in osteosarcoma and a sarcomatoid carcinoma case, respectively. JAK1 amplification and DDR2M754I were found in the same patient. The IDH2 mutation and JAK1 amplification could find potential applications for JAK1 and IDH2 inhibitors respectively. Similarly, cancers having DDR2 mutations are known to respond to multikinase inhibitors such as Imatinib and Dasatinib, thus making a strong case for the potential repurposing of these drugs in sarcomas. ~93% of patients demonstrated genome-wide instabilities as evidenced by LOH, LST, TAI, and high TMB. Homologous Recombinant deficiency was found in 66.7% of patients. Although this is a small patient population, the high HRD+ percentages point to the underappreciated importance of HRD testing in sarcoma and herald the use of PARPi therapy for sarcoma. Conclusions: We identified several actionable mutations in rare sarcoma cases. These findings highlight the power of comprehensive genome profiling like the OncoIndx panel and warrant further studies on the role of IDH2, JAK1, and BRAF fusion in sarcomas. Moreover, they also present a strong potential case for repurposing of TKI such as Imatinib and Dasatinib in sarcomas.