Mitochondrial DNA A10398G Mutation is not Associated with Breast Cancer Risk in a Sample of Iraqi Women

Haneen M Ismaeel,Hayba Q Younan,Rawaa A Zahid

doi:10.19026/crjbs.5.5453

Abstract

The aim of this study was to investigate if there is a relationship between mtDNA polymorphism (A10398G) and breast cancer in a sample of 59 Iraqi women. Breast cancer is the second most common diagnosed cause of cancer death in the developed countries and accounts for 23% of the total cancers. Different studies reported that breast cancer accounts for 14% of all cancer deaths in females. It is well documented that the different factors such as genetics and environment factors are involved in tumorigenesis. Mutations in the mitochondrial DNA D-loop region and somatic mutations are emerging as early genetic markers of cancer. Identification of such markers for breast cancer would prevent late detection and increase the chance of recovery and survival rate. In breast cancer different mtDNA alterations were reported. The A10398G mutation in NADH Dehyrogenase (ND3) a subunit of complex I of the Oxidative Phosphorylation process (OXPHOS) is perhaps one of the most studied mutations with conflicting reports of its association with breast cancer. Genomic DNA was extracted from 21 unrelated women with malignant tumors, 22 women with benign tumors and 16 healthy women blood donors. Subsequently, PCR amplification was performed using specific primers, PCR products were subjected to a suitable restriction enzyme. No genetic variants were identified in mtDNA among malignant tumoral group and controls while 9% of benign tumor cases exhibited the variant. Our finding indicated that A10398G polymorphism cannot be used as a biomarker for breast cancer detection in Iraqi women.

Highlights

According to the most recent Iraqi Cancer Registry in 2010, breast cancer has a propensity in young aged women; this disease is classified as the first amongst malignancies in the Iraqi population (Iraqi Cancer Board and Iraqi Cancer Registry, 2008)
All three groups of malignant, benign and controls a total of 59 sample were subjected sequentially to PCR amplification to amplify the fragment of 422 bp which harbor nucleotide position 10398 (Fig. 1)
Mitochondrial DNA is a rich template for genetic variation that exhibits exclusively maternal transmission (Chan, 2006; Ishikawa et al, 2008)

Summary

Introduction

According to the most recent Iraqi Cancer Registry in 2010, breast cancer has a propensity in young aged women; this disease is classified as the first amongst malignancies in the Iraqi population (Iraqi Cancer Board and Iraqi Cancer Registry, 2008). In a cross-sectional, questionnaire-based study comprising 387 Iraqi females and males, 75% of participants believe that early detection is the best way to control the disease occurrence (Alwan et al, 2012). For this we need to emphasize on the importance of genetic screening approaches and to test potential genetic markers, one approach is to test mitochondrial DNA possible markers for early detection of this disease. Mitochondria DNA (mtDNA) is a double stranded DNA molecule of 16569nt, compactly organized encoding for 37 genes 13 of which are involved in cellular energy production. The mtDNA mutation frequency is 20 times greater than that of nuclear DNA (Anderson et al, 1981; Ishikawa et al, 2008)

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