title: Linking obesity to colorectal cancer: recent insights into plausible biological mechanisms.
abstract: OBJECTIVE
  This review will examine the recent scientific literature on the mechanisms that are thought to link obesity to colorectal cancer (CRC) risk.
  
  
  RESULTS
  Obesity has emerged as a leading environmental risk factor for the development of CRC. However, the mechanisms underlying this relationship have not yet been fully elucidated. Recent literature has focused on inflammatory processes, adipokines, and estrogen. Obesity-enhanced inflammation is largely orchestrated by increases in adipose tissue macrophages leading to the secretion of inflammatory cytokines including tumor necrosis factor-α, monocyte chemoattractant protein-1, and interleukin-6, all of which are linked to CRC. Adiponectin is decreased with obesity and has been reported to be negatively associated with CRC, whereas leptin, which is increased, is positively associated with the disease. Estrogen has been shown to influence CRC, although its role remains controversial; some studies have implicated estrogen as being protective, whereas others have suggested it to be a risk factor. We highlight the most important recent advances that have been made on the aforementioned mechanisms that are thought to link obesity to CRC.
  
  
  CONCLUSIONS
  A better understanding of the mechanisms linking obesity to CRC risk is necessary for the design of effective treatment approaches in future clinical trials.
authors.affiliation: Department of Pathology, Microbiology, and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29209, USA.
authors.forename: Catherine R
authors.initials: CR
authors.lastname: Guffey
authors.forename: Daping
authors.initials: D
authors.lastname: Fan
authors.forename: Udai P
authors.initials: UP
authors.lastname: Singh
authors.forename: E Angela
authors.initials: EA
authors.lastname: Murphy
mesh_terms: D052242:Adiponectin / Q000097:blood; D000273:Adipose Tissue / Q000378:metabolism / Q000473:pathology; D018932:Chemokine CCL2 / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000209:etiology / Q000473:pathology*; D004967:Estrogens / Q000097:blood; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000473:pathology; D015850:Interleukin-6 / Q000378:metabolism; D020738:Leptin / Q000097:blood; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D009765:Obesity / Q000150:complications / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D052242:Adiponectin; D018932:Chemokine CCL2; D004967:Estrogens; D015850:Interleukin-6; D020738:Leptin; D014409:Tumor Necrosis Factor-alpha