Clinical implications of next-generation sequencing on pediatric solid tumors.

Abstract

e22012 Background: To assess the impact of next-generation sequencing (NGS) on Chinese pediatric cancer, we reported the first study of largest cohort in Chinese children with genomic landscape and highlighted the potential application with respect to molecular diagnosis and predictive biomarkers etc. Methods: A retrospective analysis was conducted on patients aged < 19 years diagnosed with solid tumors sequenced by targeted NGS panel. Somatic variants were analyzed following CAP/CLIA-certificated workflows, including Single Nucleotide Variant (SNV), Copy Number Variation (CNV), large insertion and deletions (Lindel) and gene rearrangements. Results: A total of 356 patients enrolled with three major cancer types including osteosarcoma (OS) (n = 78), rhabdomyosarcoma (RMS) (n = 51), Ewing sarcoma (EWS) (n = 13). Hepatocellular carcinoma (n = 9), medulloblastomas (n = 7) and colorectal adenocarcinoma (n = 5) were also included. 3487 somatic alterations were identified, TP53 (16%), EWSR1 (8.7%), CDKN2A (7.8%), BCOR (7%) and RB1 (5.6%) rank the top five reported. TP53 (21% % vs 7.9%), RB1 (10% vs 5.3%) mutations showed higher frequency in OS and BCOR (14% vs 17.6%) showed lower frequency in RMS compared to published paper (Gröbner et al 2018). We found PIK3CA mutations presented in RMS with 11.7% frequency, twice than reported (5.8%), mostly occurring at the known oncogenic codon E545. The obscure boundary of soft tissue tumor and bone tumor perplexed the pathologic diagnosis, NGS provide an important auxiliary examination. In 140 soft tissue tumor and bone tumor patients, 14.2% patients were further diagnosed with different subtype, 4.2% patients with unknown subtype were diagnosed with a specified subtype by supportive genetic alterations. Moreover, 41.5% (138/356) patients received treatment recommended . Twelve NTRK-fusions were detected and the patients were recommended therapy method upon Larotrectinib, recruitment in matched clinical trial is still on-going. Conclusions: We investigated the different genetic profiling of Chinese pediatric solid cancer and found the clinical value of NGS in pathological diagnosis and biomarker discovery.