title: Lipid Peroxidation and Antioxidant Status in Patients with Medullary Thyroid Carcinoma: A Case-Control Study.
abstract: BACKGROUND
  Oxidative stress or oxidant/antioxidant imbalance has a crucial role in the pathogenesis of some diseases like cancer. Medullary thyroid carcinoma (MTC) originates in the thyroid parafollicular cells and includes 3-4% of the malignant neoplasms that have an effect on this gland. The aetiology of MTC has not been clarified. However, oxidative stress may be one of the factors involved.
  
  
  OBJECTIVE
  The aim of the current study was to evaluate the antioxidant enzyme activity of catalase (CAT), Glutathione (GSH), total antioxidant capacity (TAC) and the levels of the lipid peroxidation product malondialdehyde (MDA) in blood samples of MTC patients as compared to healthy controls.
  
  
  METHODS
  A case-control study was designed enrolling patients with confirmed MTC diagnosis and age-and sex group matched healthy volunteers referred to the clinic of the Research Institute for Endocrine Sciences, Tehran, Iran from April 2013 to July 2015. Fasting blood samples were taken for study. Catalase, GSH, MDA and TAC levels were measured by colorimetry using commercial kits (ZellBio GmbH, Germany). Data were analysed using SPSS 17 software, comparing mean±SD through t-test and difference between proportions through chi-square.
  
  
  RESULTS
  No statistical difference was observed in the demographic characteristic between cases and controls. The final MTC group included 40 males and 45 females with a mean age of 30±12.9 year, and the control group 40 males and 47 females, with a mean age of 31.2±12.3 year. Anthropometric parameters, dietary and thyroid hormones levels (T3, T4 and TSH) were similar. Serum TAC (p=0.015), GSH (p=0.029) and CAT (p<0.001) levels were found to be significantly lower in the MTC patients, while serum MDA levels were significantly higher in MTC patients than controls (p<0.001).
  
  
  CONCLUSIONS
  These preliminary findings suggest that oxidant/antioxidant imbalance may be associated with or possibly indicate an increased risk to medullary thyroid carcinoma. Further studies are needed to explore these findings.
authors.affiliation: Ph.D. Candidate in Clinical Biochemistry, Department of Biochemistry, School of Medicine, Hamadan University of Medical Sciences , Hamadan, Iran .
authors.forename: Seyed-Mostafa
authors.initials: SM
authors.lastname: Hosseini-Zijoud
authors.affiliation: Associate Professor of Endocinology, Department of Internal Medicine, Faculty of Medicine, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Seyed Alireza
authors.initials: SA
authors.lastname: Ebadi
authors.affiliation: Professor of Clinical Biochemistry, Department of Biochemistry, School of Medicine, Hamadan University of Medical Sciences , Hamadan, Iran .
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Goodarzi
authors.affiliation: Associate Professor of Biochemistry, Cellular and Molecular Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Mehdi
authors.initials: M
authors.lastname: Hedayati
authors.affiliation: Assistant Professor, Department of Clinical Biochemistry, Department of Biochemistry, School of Medicine, Hamadan University of Medical Sciences , Hamadan, Iran .
authors.forename: Roghayeh
authors.initials: R
authors.lastname: Abbasalipourkabir
authors.affiliation: Assistant Professor, Department of Cardiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences , Tehran, Iran .
authors.forename: Mohammad Parsa
authors.initials: MP
authors.lastname: Mahjoob
authors.affiliation: Associate Professor of Epidemiology, Research Center for Health Sciences and Department of Epidemiology, School of Public Heath, Hamadan University of Medical Sciences , Hamadan, Iran .
authors.forename: Jalal
authors.initials: J
authors.lastname: Poorolajal
authors.affiliation: Professor of Epidemiology, Center for Technological Development in Health, Oswaldo Cruz Foundation , Rio de Janeiro, Brazil .
authors.forename: Fabio
authors.initials: F
authors.lastname: Zicker
authors.affiliation: Professor of Clinical Biochemistry, Department of Biochemistry, School of Medicine, Hamadan University of Medical Sciences , Hamadan, Iran .
authors.forename: Nasrin
authors.initials: N
authors.lastname: Sheikh
keywords: Catalase; Glutathione; Malondialdehyde; Total antioxidant capacity