title: Cancer morbidity in rheumatoid arthritis: role of estrogen metabolites.
abstract: Estrogen metabolites have been implicated in rheumatoid arthritis (RA) and cancer, although the mechanism remains unestablished. Some estrogen metabolites, which are used for the assessment of cancer risk, play an important role in RA. The pathways by which malignancies associated with RA remain elusive. Possible mechanism involves enzymatic or nonenzymatic oxidation of estrogen into catecholestrogen metabolites through semiquinone and quinone redox cycle to produce free radicals that can cause DNA modifications. Modifications of DNA alter its immunogenicity and trigger various immune responses leading to elevated levels of cancer and RA antibodies. However, the role of different estrogen metabolites as a mediator of immune response cannot be ruled out in various immune-related diseases.
authors.affiliation: Department of Clinical Biochemistry, College of Medicine, King Khalid University, Abha 641, Saudi Arabia.
authors.forename: Wahid Ali
authors.initials: WA
authors.lastname: Khan
authors.forename: Mohd Wajid Ali
authors.initials: MW
authors.lastname: Khan
mesh_terms: D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D004967:Estrogens / Q000276:immunology / Q000378:metabolism*; D002393:Estrogens, Catechol / Q000276:immunology / Q000378:metabolism; D005609:Free Radicals / Q000276:immunology / Q000378:metabolism; D006801:Humans; D009369:Neoplasms / Q000150:complications / Q000276:immunology / Q000378:metabolism / Q000401:mortality* / Q000473:pathology; D010084:Oxidation-Reduction; D011809:Quinones / Q000276:immunology / Q000378:metabolism
chemical_list: D004967:Estrogens; D002393:Estrogens, Catechol; D005609:Free Radicals; D011809:Quinones