Mutation screening in the mitochondrial D-loop region of tumoral and non-tumoral breast cancer in Iranian patients.

The mitochondrial DNA (mtDNA) mutations in mitochondrial coding and non coding regions seem to be important in carcinogenesis. The aim of this investigation was to evaluate coding region (mt-tRNA(Phe) and tRNA(Pro)) and non-coding sequence, mitochondrial displacement loop (mtDNA D-loop), in the cancerous and non-cancerous lesions of Iranian patients with breast cancer (BC). Genomic DNA was extracted from 50 breast tumors and surrounding normal tissue pairs as well as from 50 unrelated normal breast tissues from Iranian Kurdish population. Subsequently, PCR amplification was performed using specific primers, and then PCR products were subjected to direct sequencing. 41 genetic variants were identified in mtDNA D-loop among tumoral and non-tumoral tissues but not in tRNA(Phe) and tRNA(Pro) sequences. Our findings indicated that C182T, 194insT, 285insA and 16342delT were just found in BC tumors whereas 302insC, C309T and C16069T found in both tumors and surrounding normal tissues. Although our findings showed that the observed genetic variations were not restricted to breast cancer tissues, some genetic changes were found only in BC tumors. Our results, in agreement with the evidence from earlier studies, confirm that the mtDNA genetic alterations might be implicated in tumor initiation, progression and development.