Background: MMP9, as a member of the MMPs family, codes a protein that is able to provide suitable infrastructures for the migration of cancer cells and angiogenesis within tumor. The aim of this study was to investigate the relationship between -1562 C> T polymorphism in MMP9 promoter and progression of breast cancer in northwest of Iran.

Materials and Methods:  In this case-control study, 187 females from northwest of Iran were involved. Polymorphism of interest was determined by PCR-RFLP method using enzyme PaeI and statistical analysis was done by Med Calc software.

Results: Distribution of CC genotype in cancer and control groups was,44 and 62.5, tespectively and distribution of CT genotype in cancer and control groups was 56 and 37.5, respectively, In the statistical analysis, χ² and p value were respectively, 5.4 and 0.01. There is a significant association between this polymorphism and lymph nodes involvement and presence of tumor larger than 2cm³ (respectively p= 0.005 and p = 0.03). The results of this study showed -1562 C> T polymorphism in MMP9 promoter is associated with stage II and higher stages of breast cancer in our population. Furthermore, CT genotype may increase the risk of lymph node metastasis and presence of tumor larger than 2 cm³ (OR= 4).

Conclusion: According to the results of this study, MMP9 (-1562 C> T) polymorphism may be used as a biomarker for breast cancer prognosis. Although, to achieve more definitive results, it is necessary to examine a larger population.