Journal of Rafsanjan University of Medical Sciences

Background and Objectives:�Matrix metalloproteinase-9 is one of the proteolytic enzymes that serves in the digestion of collagen and gelatin. A single cytosine to thymidine substitution in AP-1 site in the promoter causes over-expression in the thymidine allele. The aim of this study was the detection of thymidine base function on ducts and lobules cells of breast tissue for entering the cancer step.

Materials and Methods: This research is a case-control study involving 90 breast cancer patients without metastasis to other tissues from Omid hospital between 2006-2008 and 100 healthy controls. Sample genotypes were detected by RFLP-PCR technique. At the end genotype of samples was detected by direct sequencing. Also the existence of tumor in ducts and, lobules cells of breast tissues in all the respondents was determined by mammography and expert physicians.

Results: Comparison of the case and control groups showed T/T genotype and C/T genotype in 0% and 9% of the control groups, and 2.3% and 22.2% of the patients. Therefore, thymine nucleotide at AP-1 region of MMP-9 gene could be a facilitated factor for initiation of breast cancer, and could increase the risk of initiation and development of breast tumor (p= 0.004), (CI=1.438-7.423�OR=3.27).

Conclusions: The positive association between the thymine nucleotide at AP-1 site and creation of tumor in breast tissue can arise from enzyme protease activity and result in the digestion of growth factor inhibitors and release of these factors.

Key words: Breast Cancer, Matrix metalloproteinase-9, Base substitution

Funding:�This study was funded by Graduate Studies Office of Isfahan University.

Conflict of interest: None declared.

Ethical approval: The Ethics Committee of Isfahan University approved the study.