Association of single nucleotide polymorphisms in promoter of matrix metalloproteinase-2, 8 genes with bladder cancer risk in Northern India

Objective: Matrix metalloproteinases (MMPs) are expressed in melanocytes and their overexpression has been linked to tumor development, progression, and metastasis. At the genetic level, following functional promoter polymorphisms are known to modify the gene transcription: -1306 C > T, -735 C > T in MMP2, and 799 C > T in MMP8 gene. Hence we hypothesize that functional polymorphisms in the 2 MMP SNPs in promoter region may modulate the risk for bladder cancer (BC) progression in North Indian population.

Materials and methods: Genotyping for these polymorphisms were done in a group of 200 BC and 200 age matched, similar ethnicity unrelated healthy controls using PCR-based methods. Two-sided χ(2), Cox-regression was utilized to evaluate the associations between genotype and various clinical and epidemiologic factors. Multivariate analyses were conducted using logistic regression, adjusting for known BC confounders such as age and gender. Survival analysis was done using the Kaplan-Meier method and differences in survival were assessed using the log rank test.

Results: Individuals with MMP2 (-1306) TT genotype as well as T allele were at higher risk of BC (P, 0.042; OR, 2.85; P, 0.001; OR, 1.76). This effect was even more apparent in case of CT+TT (P < 0.001; OR, 2.61). In MMP2 (735), CT+TT demonstrated significant risk (P, 0.034; OR, 1.66). In MMP8 (799), reduced risk was observed with TT genotype (P, 0.006; OR, 0.27). Haplotype analysis showed that individuals with haplotype 735C-1306T and 735T-1306C were at 1.9- and 1.5-fold higher risk. MMP2 -1306CC in combination with MMP8 799CT genotype showed protective effect. The genotype CT and CT+TT of MMP2 1306C > T were associated with high risk of recurrence in BCG treated patients (HR, 4.32; P, 0.006 and HR, 2.06; P, 0.047) thus showing reduced recurrence free survival (CT+TT/CC = 34/45 months; log rank P, 0.039).

Conclusion: Our data suggested that variant allele of MMP2 1306C > T was associated with high risk of tumor recurrence and reduced recurrence free survival in superficial BC patients.