MMP9 Promoter Polymorphism (-1562 C/T) Does not Affect the Serum Levels of Soluble MICB and MICA in Breast Cancer

Background: The role of Matrix Metalloproteinase 9 (MMP9) in tumor invasion and progression is prominent. A single nucleotide polymorphism (SNP) in the promoter region of MMP9 (-1562 C/T) increases the transcription and expression of this gene. On the other hand, MHC class I chain-related protein A and B (MICA/B) in soluble forms may impair tumor immunogenicity by reducing Natural Killer Group 2D (NKG2D) densities on NK cells and MMP9 enzyme activity has a prominent role in shedding of MICA/B. Objectives: To investigate the association between MMP9 (-1562 C/T) polymorphism and serum MICA/B level in breast cancer patients. Methods: In this case-control study, 105 patients with breast cancer and 100 healthy age-matched women were selected from Yazd hospitals, Iran. The polymorphism of MMP9 (-1562 C/T) was determined by PCR-RFLP. Concentration of MICB and MICA in the sera of breast cancer patients and healthy women were measured using ELISA method. Results: The frequency of CC, CT and TT genotypes and T allele of the MMP9 (-1562 C/T) did not show significant differences between breast cancer patients and healthy donors (p>0.05). On the other hand, the mean serum levels of MICB and MICA were significantly elevated in patients compared with healthy individuals (p<0.05). In patients with MMP9CC genotype, the mean serum MICB concentration was significantly higher than those patients with CT polymorphism (p<0.05). Although the mean of blood MICA concentration in patients with the CT genotype was higher than those patients with CC genotype, the difference was not statistically significant. Conclusion: The T allele of the MMP9 (-1562 C/T) does not show a correlation with serum levels of MICA and MICB in breast cancer patients.