title: Molecular subtypes in cancers of the gastrointestinal tract.
abstract: Malignancies of the gastrointestinal tract are among the most common human cancers. The distinct tissues of origin give rise to a diverse set of diseases, such as colorectal cancer, pancreatic carcinoma and gastric cancers, with each associating with specific clinical features. Genomic and transcriptomic analyses have further defined the heterogeneity that occurs within these cancers by identifying so-called molecular subtypes. These subtypes are characterized by specific genetic aberrations and expression signatures that suggest important biological differences. Although at first sight this subdivision of organ-specific cancers might increase the complexity of classification, closer analysis suggests that the subtypes detected in the various malignancies are recurring. For example, nearly all gastrointestinal cancers appear to present with subtypes that are either characterized by a mesenchymal gene expression signatures, extensive immune infiltration or metabolic dysregulation. Additionally, in each of the gastrointestinal malignancies, a 'canonical' subtype is recognized that retains characteristic features of the epithelial tissue of origin. These common themes can enhance our collective understanding of these malignancies, and could perhaps be therapeutically exploited. In this Review, the identification of subtypes in the various gastrointestinal cancer types are discussed along with how they could be incorporated into clinical practice.
authors.affiliation: Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Maarten F
authors.initials: MF
authors.lastname: Bijlsma
authors.affiliation: Division of Molecular Pathology, The Institute of Cancer Research, 15 Cotswold Road, London SM2 5NG, UK.
authors.forename: Anguraj
authors.initials: A
authors.lastname: Sadanandam
authors.affiliation: Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore.
authors.forename: Patrick
authors.initials: P
authors.lastname: Tan
authors.affiliation: Laboratory for Experimental Oncology and Radiobiology, Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Louis
authors.initials: L
authors.lastname: Vermeulen
mesh_terms: D005770:Gastrointestinal Neoplasms / Q000145:classification* / Q000235:genetics / Q000628:therapy; D020869:Gene Expression Profiling / Q000379:methods; D052138:Genes, Neoplasm / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D058990:Molecular Targeted Therapy / Q000379:methods; D009154:Mutation / Q000235:genetics; D018358:Neuroendocrine Tumors / Q000145:classification / Q000235:genetics / Q000628:therapy; D010641:Phenotype; D009626:Terminology as Topic