Background: We have conducted the Nationwide Cancer Genome Screening Project in Japan since April 2015 using Next Generation Sequencing in advanced non-colorectal gastrointestinal (GI) cancer (aNon-CRC), called as the SCRUM-Japan GI-SCREEN. Methods: This study is ongoing with 20 major cancer centers. Patients with aNon-CRC, who plan to or receive chemotherapy were eligible. DNA and RNA were extracted from FFPE tumor samples and were analyzed by the Oncomine Cancer Research Panel (OCP) which allows to detect gene mutation, copy number variant (CNV) and fusions across 143 genes in a CLIA certified CAP accredited laboratory. The detected genomic variant data were classified according to whether genetic drivers of cancer including gain- and loss-of-function or single nucleotide variant based on the Oncomine Knowledgebase. In this presentation, we show the results of advanced gastric cancer (aGC) cohort. Results: As of October 31^st in 2016, a total of 565 aGC samples were analyzed. The sequence with the OCP was successfully performed in 425 (75.2%). Out of 475 patients except for the 90 patients in which precise data is not collected, the proportion of histology type is followed; intestinal type 44.6%, diffuse type 54.5%, other 0.6%, unknown 0.2%. Out of 406 samples of which results were available, the frequently detected mutations were TP53 (47.8%), PIK3CA (8.6%), KRAS (5.4%), SMAD4 (4.9%), TET2 (4.4%), APC (3.9%), ERBB2 (3.7%) and CNVs were ERBB2 (10.8%), CCNE1 (9.4%), KRAS (3.7%), ZNF217 (3.2%), FGFR2 (2.7%), and MET (2.5%). FGFR3-TACC3 fusion, WIPF2-ERBB2 fusion and EGFR vIII were detected in 2, 1, and 2 cases, respectively. Conclusions: This nationwide screening system is efficient to detect rare gene alterations in aGC. This novel knowledge provides an intriguing background to investigate new target approaches and represents a progress toward more precision medicine. Clinical trial information: UMIN000016344.