Table 2.

Summary of results from studies discussed in Section 3.1.

Author	Subgroups	Association Response	Differential Expressed Genes	Pathways	External Validation
TCGA, Australia, Brazil, Canada, Germany, South-Korea, Moldova, Netherlands, Poland, Russia, Ukraine United Kingdom, United States of America, Vietnam [31]	EACs and CIN gastric cancers jointly formed a group distinct from EBV, MSI or GS tumors	NA	NA	NA	No
Bornschein, United Kingdom, Germany [33]	Three subgroups	Association with median overall survival (Group 1: 25.9 m vs. Group 2: 45.2 m vs. Group 3: 83.5 m; p = 0.019)	Adjusted p-value <= 0.05 Group 1 versus 3317 genes Group 3 versus 2243 genes Group 1 versus 2204 genes 82 candidate genes for discrimination between subtypes	Group 1 “Ribosome”, “Fatty Acid Metabolism”, “Oxidative Phosphorylation”, pathways involved in nucleic acid turnover Group 2 “Steroid Hormone Biosynthesis”, “Peroxisome”, “Primary Bile Acid Biosynthesis” and pathways involved in metabolic processes. Group 3 “Antigen Processing and Presentation”, “Chemokine Signaling Pathways”, “Natural Killer Cell-Mediated Cytotoxicity”, and pathways involved in immune-response	Subtypes confirmed successfully in all four cohorts, association with overall survival consistent in BELFAST and SINGAPORE cohorts. -OCCAMS RNASeq cohort with 154 EAC and GEJ adenocarcinomas -BELFAST Affymetrix cohort with 63 EAC -SINGAPORE Affymetrix cohort with 191 gastric cancers -Asian Cancer Research Group Affymetrix cohort with 300 gastric cancers
Kim, United States of America [34]	Three subgroups	Association with recurrence free survival (worse in cluster B)	p < 0.002 and 1.5-fold differences between the groups cluster A versus B 2344 genes cluster B versus C 1489 genes 452 overlapping genes of the 2344 genes and 1489 genes, from which 10 selected for validation	Putative networks listed top network associated with over-representation of NF-kB	10 genes tested with qRT-PCR on RNA from FFPE in 52 EAC SPARC and SPP1 associated with poor overall survival