Breast Cancer and Mitochondrial Dna Mutations in Kurdish Women: A Case-Control Study From Sulaymaniyah, Iraq.

Abstract

The molecular basis of breast cancer has been thoroughly investigated in the last decade. Many nuclear susceptibility genes were discovered. Moreover, research about mitochondrial DNA (mtDNA) mutations and mitochondrial haplogroup determinants (single nucleotide polymorphism; SNP) has explored their potential role in cancers in general and breast cancer in particular.This study is to identify breast cancer-related SNPs and mtDNA haplogroups among Kurdish women living in Sulaymaniyah/Iraq. This case-control study was conducted in Kurdistan Institute for Strategic and Scientific Research (KISSR) / Molecular Lab in Sulaymaniyah in collaboration with a specialized lab in South Korea. Twenty women with breast cancer and 20 women with benign breast diseases were enrolled. The entire mitochondrial genome of 40 breast tissue specimens was sequenced. Haplogrep 2.0 was utilized for haplogroup identification. Statistical Analysis was performed using Chi-square and Fisher's exact tests.A total of 547 mutations (Cancer, n=344 and Control, n=203) were identified including 15 first-reported mutations. HV haplogroup in the cancer samples was a risk factor for the development of breast cancer (p=0.002) compared to H haplogroup in the control samples (p =0.006) (Odd Ratio [OR] = 28.00). Furthermore, SNP (A8860G) was an additional risk compared to other randomly selected SNPs (A750G, A1438G, and C7028T) (p ˂0.05 and OR >1). In conclusions; the association of certain mtDNA haplogroups and SNPs with breast cancer risk is not new. Unlike studies performed in other populations of the world figuring out A10398G as the risky SNP, our study identified A8860G in the Kurds. Geographic and ethnic variations between human populations do exist, so an SNP that is common in one population group may be much rarer in another. Hence, more research on the molecular biology of breast cancer in our locality is warranted to clarify the situation.