title: Systematic review of the association between circulating interleukin-6 (IL-6) and cancer.
abstract: Our aim was to systematically review the epidemiologic evidence for an association of circulating interleukin-6 (IL-6), an inflammatory cytokine and cancer. We systematically searched electronic databases Embase, Medline and Web of Science for the studies of circulating IL-6 and any form of cancer. We identified and reviewed 189 discrete studies, consisting of 177 prevalent studies and three prospective studies. Cancer patients' IL-6 concentrations were higher than healthy controls' in most studies, but the results of investigations comparing IL-6 in cancer patients and individuals with benign diseases were less consistent. Due to the small number of prospective studies it is impossible to determine whether IL-6 is causally related to cancer. Large prospective studies of circulating IL-6 or studies using the functional variants of the IL-6 gene as instruments for circulating IL-6 concentrations would provide information on possible aetiological links between IL-6 and malignancy.
authors.affiliation: Department of Social Medicine, University of Bristol, UK.
authors.forename: Katriina
authors.initials: K
authors.lastname: Heikkilä
authors.forename: Shah
authors.initials: S
authors.lastname: Ebrahim
authors.forename: Debbie A
authors.initials: DA
authors.lastname: Lawlor
mesh_terms: D004812:Epidemiologic Methods; D006801:Humans; D007249:Inflammation / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D009369:Neoplasms / Q000175:diagnosis* / Q000209:etiology
chemical_list: D015850:Interleukin-6