Prognostic significance of MMP-1 and MMP-3 functional promoter polymorphisms in colorectal cancer

Abstract

Purpose: Matrix metalloproteinase (MMP) belongs to a large group of proteases capable of breaking essentially all components of the extracellular matrix. They are implicated in all steps of tumorogenesis, cancer invasion, and metastasis. Among them, metalloproteinase type 1 (MMP-1) is implicated in tumor invasion and metastasis in different types of cancers including colorectal cancer in which its expression was correlated with poor prognosis. A polymorphism in the promoter region of the MMP-1 gene leads to a variation of its level of transcription.

Study design: MMP-1 -1607ins/delG and MMP-3 - 1612 ins/delA promoter polymorphisms were genotyped by multiplex PCR from 201 colorectal cancer patients. The median follow-up of patients was 30 months. The MMP genotypes were correlated to clinical outcome.

Results: Patients with the -1607insG/-1607insG MMP-1 genotype had significantly worse specific survival than the others in the whole series (P < 0.04), in stage I to III patients (P < 0.001), and in patients stage I and II (P < 0.01). In multivariate analysis, MMP-1-1607insG allele showed to be an independent poor prognostic factor after adjustment on stage, age, and the use of adjuvant chemotherapy. MMP-3 polymorphism was not associated with survival.

Conclusions: In the subgroups of nondistant metatastic patients (stages I and II, and stages I-III), an inverse relation between the number of MMP-1-1607insG allele and survival was observed suggesting a gene dosage effect. Our results are consistent with the importance of MMP-1-1607ins/delG functional polymorphism in regulating transcription level and with the relationship between MMP-1 expression and cancer invasion, metastasis, and prognosis.