Actionable gene-based classification toward precision medicine in gastric cancer.
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ABSTRACT: BACKGROUND:Intertumoral heterogeneity represents a significant hurdle to identifying optimized targeted therapies in gastric cancer (GC). To realize precision medicine for GC patients, an actionable gene alteration-based molecular classification that directly associates GCs with targeted therapies is needed. METHODS:A total of 207 Japanese patients with GC were included in this study. Formalin-fixed, paraffin-embedded (FFPE) tumor tissues were obtained from surgical or biopsy specimens and were subjected to DNA extraction. We generated comprehensive genomic profiling data using a 435-gene panel including 69 actionable genes paired with US Food and Drug Administration-approved targeted therapies, and the evaluation of Epstein-Barr virus (EBV) infection and microsatellite instability (MSI) status. RESULTS:Comprehensive genomic sequencing detected at least one alteration of 435 cancer-related genes in 194 GCs (93.7%) and of 69 actionable genes in 141 GCs (68.1%). We classified the 207 GCs into four The Cancer Genome Atlas (TCGA) subtypes using the genomic profiling data; EBV (N?=?9), MSI (N?=?17), chromosomal instability (N?=?119), and genomically stable subtype (N?=?62). Actionable gene alterations were not specific and were widely observed throughout all TCGA subtypes. To discover a novel classification which more precisely selects candidates for targeted therapies, 207 GCs were classified using hypermutated phenotype and the mutation profile of 69 actionable genes. We identified a hypermutated group (N?=?32), while the others (N?=?175) were sub-divided into six clusters including five with actionable gene alterations: ERBB2 (N?=?25), CDKN2A, and CDKN2B (N?=?10), KRAS (N?=?10), BRCA2 (N?=?9), and ATM cluster (N?=?12). The clinical utility of this classification was demonstrated by a case of unresectable GC with a remarkable response to anti-HER2 therapy in the ERBB2 cluster. CONCLUSIONS:This actionable gene-based classification creates a framework for further studies for realizing precision medicine in GC.
SUBMITTER: Ichikawa H
PROVIDER: S-EPMC5664811 | biostudies-literature | 2017 Oct
REPOSITORIES: biostudies-literature
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