The MMP-2 and MMP-9 promoter polymorphisms and susceptibility to salivary gland cancer

Matrix metalloproteinases (MMPs) are a family of endopeptidases that may play an important role in the development of salivary gland cancer (SGC). MMP-2 and MMP-9, members of the gelatinase protein family, are capable of degrading type IV collagen of basement membranes, and their overexpression is often associated with tumor aggressiveness and poor prognosis. The aim of this study was to establish the role of single nucleotide polymorphisms (SNPs) in MMP-2 and MMP-9 genes as putative susceptibility factors for the development of SGC.

The MMP-2 -1306 C>T, MMP-2 -1575 G>A and MMP-9 -1562 C>T polymorphisms were analyzed in 93 SGC cases and 100 controls using PCR-RFLP.

The T allele for the MMP-2-1306 C>T polymorphism exhibited its effect in heterozygous carriers, increasing the risk for SGC (odds ratio/OR 1.98, 95% CI 1.07-3.65, p=0.03). According to the dominant model, CT+TT genotypes had a 2-fold increased risk of developing SGCs (p=0.02).When the dominant model was applied for the MMP2 -1575 G>A, individuals with GA+AA genotypes exhibited a 1.77-fold increase in cancer risk, but with borderline significance (p=0.049). Heterozygous carriers of the variant T allele for the MMP-9 -1562 C>T polymorphism had roughly a 2-fold increase in susceptibility for SGC compared to wild type homozygotes (CC) (p=0.02).

Our findings suggest MMP-2-1306 C>T and MMP-9-1562 C>T polymorphisms genotypes seem to influence the development of SGCs, whereas MMP-2 -1575 G>A seems to be of a minor importance.