
Abstract Background Gastric cancer (GC) patients from European (EU) and especially Latin American (LATAM) countries are underrepresented in previous large-scale multi-omic studies that have identified clinically relevant subgroups. The LEGACY study aimed to profile the molecular and immunological features of GCs from EU and LATAM countries. Methods Tumor biopsies from 95 EU and 56 LATAM GCs were profiled with immunohistochemistry (CD3, CD8, FOXP3, PD-L1, MSI and HER2), Nanostring mRNA expression analyses, and microbiome sequencing. Results Immune profiling identified four distinct immune clusters: a T cell dominant cluster with enriched activation pathways, a macrophage dominant cluster and an immune excluded microenvironment which were equally distributed among the countries. A fourth cluster of mostly Mexican patients consisted of excessive T cell numbers accompanied by enhanced cytokine signaling in absence of enhanced antigen presentation and cytotoxicity signatures and a strong association with H. pylori infection. Discussion Both EU and LATAM countries have GCs with a T cell inflamed microenvironment that might benefit from checkpoint inhibition. We identified a highly inflamed GC subgroup that lacked antigen presentation and cytotoxicity associated with H. pylori CagA-positive strains, suggesting their contribution to tumor immune tolerance. Future studies are needed to unravel whether these cancers benefit from immunotherapy as well.
Male, ENFERMEDADES::neoplasias::neoplasias por localización::neoplasias del sistema digestivo::neoplasias gastrointestinales::neoplasias gástricas, FENÓMENOS Y PROCESOS::fenómenos microbiológicos::microbiota::microbiota intestinal, Adenocarcinoma, Article, DISEASES::Neoplasms::Neoplasms by Site::Digestive System Neoplasms::Gastrointestinal Neoplasms::Stomach Neoplasms, Helicobacter Infections, Stomach Neoplasms, Tumor Microenvironment, Humans, Intestins - Microbiologia, DISEASES::Neoplasms::Neoplasms by Histologic Type::Neoplasms, Glandular and Epithelial::Carcinoma::Adenocarcinoma, FENÓMENOS Y PROCESOS::fenómenos fisiológicos celulares::microambiente celular::microambiente tumoral, Aged, DENOMINACIONES GEOGRÁFICAS::localizaciones geográficas::Américas::Latinoamérica, GEOGRAPHICALS::Geographic Locations::Americas::Latin America, Helicobacter pylori, Microbiota, Middle Aged, Gastrointestinal Microbiome, ENFERMEDADES::neoplasias::neoplasias por tipo histológico::neoplasias glandulares y epiteliales::carcinoma::adenocarcinoma, Europe, PHENOMENA AND PROCESSES::Microbiological Phenomena::Microbiota::Gastrointestinal Microbiome, Estómac - Càncer, PHENOMENA AND PROCESSES::Cell Physiological Phenomena::Cellular Microenvironment::Tumor Microenvironment, Amèrica Llatina, Female
Male, ENFERMEDADES::neoplasias::neoplasias por localización::neoplasias del sistema digestivo::neoplasias gastrointestinales::neoplasias gástricas, FENÓMENOS Y PROCESOS::fenómenos microbiológicos::microbiota::microbiota intestinal, Adenocarcinoma, Article, DISEASES::Neoplasms::Neoplasms by Site::Digestive System Neoplasms::Gastrointestinal Neoplasms::Stomach Neoplasms, Helicobacter Infections, Stomach Neoplasms, Tumor Microenvironment, Humans, Intestins - Microbiologia, DISEASES::Neoplasms::Neoplasms by Histologic Type::Neoplasms, Glandular and Epithelial::Carcinoma::Adenocarcinoma, FENÓMENOS Y PROCESOS::fenómenos fisiológicos celulares::microambiente celular::microambiente tumoral, Aged, DENOMINACIONES GEOGRÁFICAS::localizaciones geográficas::Américas::Latinoamérica, GEOGRAPHICALS::Geographic Locations::Americas::Latin America, Helicobacter pylori, Microbiota, Middle Aged, Gastrointestinal Microbiome, ENFERMEDADES::neoplasias::neoplasias por tipo histológico::neoplasias glandulares y epiteliales::carcinoma::adenocarcinoma, Europe, PHENOMENA AND PROCESSES::Microbiological Phenomena::Microbiota::Gastrointestinal Microbiome, Estómac - Càncer, PHENOMENA AND PROCESSES::Cell Physiological Phenomena::Cellular Microenvironment::Tumor Microenvironment, Amèrica Llatina, Female
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