Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. Recent high-throughput analyses of genomic alterations revealed several driver genes and altered pathways in GC. However, therapeutic applications from genomic data are limited, largely as a result of the lack of druggable molecular targets and preclinical models for drug selection. To identify new therapeutic targets for GC, we performed array comparative genomic hybridization (aCGH) of DNA from 103 patients with GC for copy number alteration (CNA) analysis, and whole-exome sequencing from 55 GCs from the same patients for mutation profiling. Pathway analysis showed recurrent alterations in the Wnt signaling [APC, CTNNB1, and DLC1 (deleted in liver cancer 1)], ErbB signaling (ERBB2, PIK3CA, and KRAS), and p53 signaling/apoptosis [TP53 and BCL2L1 (BCL2-like 1)] pathways. In 18.4% of GC cases (19/103), amplification of the antiapoptotic gene BCL2L1 was observed, and subsequently a BCL2L1 inhibitor was shown to markedly decrease cell viability in BCL2L1-amplified cell lines and in similarly altered patient-derived GC xenografts, especially when combined with other chemotherapeutic agents. In 10.9% of cases (6/55), mutations in DLC1 were found and were also shown to confer a growth advantage for these cells via activation of Rho-ROCK signaling, rendering these cells more susceptible to a ROCK inhibitor. Taken together, our study implicates BCL2L1 and DLC1 as potential druggable targets for specific subsets of GC cases.gastric cancer | copy number alteration | whole-exome sequencing | patient-derived xenograft | druggable target G astric cancer (GC) is a highly prevalent malignancy and is the third leading cause of cancer-related deaths in the world (1). In unresectable and metastatic cases, the clinical outcome for this disease remains poor (median survival is 10-14 mo) (2), and other treatment options are often limited because of the lack of effective therapeutic approaches and molecular prognostic markers (2, 3). To date, with the exception of the application of trastuzumab [ERBB2 (ErbB2 receptor tyrosine kinase 2) antagonist] or ramucirumab [VEGFR2 (Vascular endothelial growth factor receptor 2) antagonist] for advanced GC cases (4, 5), drugs that target GC on a molecular level are limited.Recent genomic studies have demonstrated the heterogeneous genomic characteristics of GC (6-10). In addition, previous studies of patients with GC by whole-genome and whole-exome sequencing (WES) have identified frequent somatic mutations in tumor suppressors such as TP53, ARID1A, APC, and FAT4, and oncogenes including PI3KCA, KRAS, and RHOA (6-10). However, these findings, although academically meaningful, are far from ready for clinical applications, largely because of the lack of identified druggable molecular targets and the availability of reliable preclinical models for validation of potential target inhibitors.To identify novel therapeutic targets for GC, we explored genomic alterations in GC through an integrated genomic data set from WE...