Correlational study on mitochondrial DNA mutations as potential risk factors in breast cancer

// Linhai Li 1, * , Lidan Chen 1, * , Jun Li 2, * , Weiyun Zhang 1 , Yang Liao 1 , Jianyun Chen 1 , Zhaohui Sun 1 1 Department of Laboratory Medicine, Guangzhou General Hospital of Guangzhou Military Command of PLA, Guangzhou, Guangdong 510010, P.R. China 2 Department of Information, No.4 Hospital of PLA, XiNing, Qinghai 810007, P.R. China * These authors have contributed equally to this work Correspondence to: Linhai Li, e-mail: mature303@126.com Keywords: mitochondrial DNA, mutation, high-throughput sequencing, breast cancer Received: January 01, 2016     Accepted: April 02, 2016     Published: April 21, 2016 ABSTRACT The presented study performed an mtDNA genome-wide association analysis to screen the peripheral blood of breast cancer patients for high-risk germline mutations. Unlike previous studies, which have used breast tissue in analyzing somatic mutations, we looked for germline mutations in our study, since they are better predictors of breast cancer in high-risk groups, facilitate early, non-invasive diagnoses of breast cancer and may provide a broader spectrum of therapeutic options. The data comprised 22 samples of healthy group and 83 samples from breast cancer patients. The sequencing data showed 170 mtDNA mutations in the healthy group and 393 mtDNA mutations in the disease group. Of these, 283 mtDNA mutations (88 in the healthy group and 232 in the disease group) had never been reported in the literature. Moreover, correlation analysis indicated there was a significant difference in 32 mtDNA mutations. According to our relative risk analysis of these 32 mtDNA mutations, 27 of the total had odds ratio values (ORs) of less than 1, meaning that these mutations have a potentially protective role to play in breast cancer. The remaining 5 mtDNA mutations, RNR2-2463 indelA, COX1-6296 C>A, COX1-6298 indelT, ATP6-8860 A>G, and ND5-13327 indelA, whose ORs were 8.050, 4.464, 4.464, 5.254 and 4.853, respectively, were regarded as risk factors of increased breast cancer. The five mutations identified here may serve as novel indicators of breast cancer and may have future therapeutic applications. In addition, the use of peripheral blood samples was procedurally simple and could be applied as a non-invasive diagnostic technique.