Background: Lung cancer is the most common cancer with 2,206,771 new cases in 2020 in worldwide. MMP9 is a member of matrix metalloproteinase family that is also known as gelatinase B or IV type collagenase (92KD). MMP9 through degrading of Extracellular Matrix (ECM) and releasing of growth factors has fundamental role in the tumorigenesis process. The C -1562 T SNP in the MMP9 promoter increases MMP9 expression and susceptibility to lung cancer. Then, the aim of this present case-control study was to investigate whether genetic variations of the MMP9 gene may constitute markers for lung cancer risk in males and in positive family history people in Iran.

Methods: This is a case-control study including 120 lung cancer patients and 100 healthy controls.

Polymorphism in the C -1562 T region was genotyped by PCR-RFLP assay. Odds Ratio (ORs) and 95% Confidence Intervals (CIs) were estimated by chi-square test from comparison of genotypes between lung cancer patients and healthy controls, using SPSS version 26.0. T-test and Image J software was also used.

Results: The distribution of C-1562T genotype was significantly associated with the risk of lung cancer (Odds Ratio [OR] = 2.56, 95% Confidence Interval [CI] = 0.06-23.82). The further stratification analyses shown that males and patients with positive family history may increase risk of lung cancer.

Conclusion: Our results indicated that the MMP9 C -1562 T polymorphism affects risk of lung cancer. In addition, men with T allele (OR = 3.94, CI = 1.47-10`.55) and patients with TT genotype and family history (OR = 2.18, CI = 1.03-4.59) exposure to higher risk of lung cancer.