Journal Article

Manganese Superoxide Dismutase and Breast Cancer Recurrence: A Danish Clinical Registry-Based Case-Control Study, and a Meta-Analysis

Autrup, Herman, Garne, Jens Peter, Hamilton-Dutoit, Stephen, Pedersen, Lars, Ahern, Thomas P., Christensen, Mariann, Ewertz, Marianne, Sørensen, Henrik T., Cronin-Fenton, Deirdre P., Lash, Timothy L.

2014

Overview

Manganese superoxide dismutase (MnSOD) inhibits oxidative damage and cancer therapy effectiveness. A polymorphism in its encoding gene (SOD2: Val16Ala rs4880) may confer poorer breast cancer survival, but data are inconsistent. We examined the association of SOD2 genotype and breast cancer recurrence (BCR) among patients treated with cyclophosphamide-based chemotherapy (Cyclo). We compared our findings with published studies using meta-analyses. We conducted a population-based case-control study of BCR among women in Jutland, Denmark. Subjects were diagnosed with non-metastatic breast cancer from 1990-2001, received adjuvant Cyclo, and were registered in the Danish Breast Cancer Cooperative Group. We identified 118 patients with BCR and 213 matched breast cancer controls. We genotyped SOD2 and used conditional logistic regression to compute the odds ratio (OR) and associated 95% confidence intervals (95% CI) of BCR. We used random-effects meta-analytic models to evaluate the association of SOD2 polymorphisms and BCR. The frequency of the SOD2-Ala allele was 70% in cases versus 71% in controls; 40% versus 44% were heterozygotes, and 30% versus 25% were homozygotes, respectively. Heterozygote and homozygote carriers of the Ala allele had no increased rate of BCR (OR = 1.1, 95%CI = 0.65, 2.0, and OR = 0.87, 95%CI = 0.47, 1.6, respectively). Five studies informed the meta-analytic models; summary estimates associating BCR for homozygote, or any inheritance of the variant Ala allele were 1.18 (95%CI = 0.74, 1.88), and 1.18, (95%CI = 0.91, 1.54), respectively. Our findings do not suggest that MnSOD enzymatic activity, as measured by SOD2 genotype, affects rates of BCR among patients treated with Cyclo.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Alleles / Amino Acid Substitution / Antineoplastic Agents, Alkylating - administration & dosage / Biology / Breast cancer / Breast Neoplasms - drug therapy / Breast Neoplasms - enzymology / Breast Neoplasms - pathology / Cancer / Cancer metastasis / Cancer recurrence / Cancer research / Cancer therapies / Care and treatment / Case studies / Chemotherapy / Confidence intervals / Cyclophosphamide / Cyclophosphamide - administration & dosage / Denmark / Enzymatic activity / Epidemiology / Female / Gene polymorphism / Genes / Genetic aspects / Genetic polymorphisms / Health aspects / Heredity / Heterozygote / Heterozygotes / Homozygote / Homozygotes / Humans / Manganese / Mastectomy / Mathematical models / Medical diagnosis / Medicine / Meta-analysis / Metastases / Metastasis / Mutation, Missense / Neoplasm Recurrence, Local - drug therapy / Neoplasm Recurrence, Local - enzymology / Neoplasm Recurrence, Local - genetics / Neoplasm Recurrence, Local - pathology / Pathology / Patients / Polymorphism / Population / Population studies / Public health / Radiation therapy / Registries / Regression analysis / Retrospective Studies / Statistical analysis / Studies / Superoxide dismutase / Superoxide Dismutase - genetics / Superoxide Dismutase - metabolism / Superoxides / Tumors / Womens health