title: Telomeres and telomere dynamics: relevance to cancers of the GI tract.
abstract: Aberrations in telomere length and telomere maintenance contribute to cancer development. In this article, we review the basic principles of telomere length in normal and tumor tissue and the presence of the two main telomere maintenance pathways as they pertain to gastrointestinal tract cancer. Peripheral blood telomeres are shorter in patients with many types of gastrointestinal tract cancers. Telomere length in tumor DNA also appears to shorten early in cancer development. Tumor telomere shortening is often accompanied by telomerase activation to protect genetically damaged DNA from normal cell senescence or apoptosis, allowing immortalized but damaged DNA to persist. Alternative lengthening of telomeres is another mechanism used by cancer to maintain telomere length in cancer cells. Telomerase and alternative lengthening of telomeres activators and inhibitors may become important chemopreventive or chemotherapeutic agents as our understanding of telomere biology, specific telomere-related phenotypes and its relationship to carcinogenesis increases.
authors.affiliation: Department of Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Nivedita
authors.initials: N
authors.lastname: Basu
authors.forename: Halcyon G
authors.initials: HG
authors.lastname: Skinner
authors.forename: Kristin
authors.initials: K
authors.lastname: Litzelman
authors.forename: Russell
authors.initials: R
authors.lastname: Vanderboom
authors.forename: Esha
authors.initials: E
authors.lastname: Baichoo
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Boardman
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D020022:Genetic Predisposition to Disease; D006801:Humans; D058990:Molecular Targeted Therapy; D010641:Phenotype; D012307:Risk Factors; D019098:Telomerase / Q000037:antagonists & inhibitors / Q000378:metabolism; D016615:Telomere / Q000378:metabolism*; D059505:Telomere Homeostasis; D059506:Telomere Shortening
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D004791:Enzyme Inhibitors; C509186:TERT protein, human; D019098:Telomerase