“…Clinical studies have now identified variant forms contained within the DNA sequences of MMP genes, or polymorphisms, for several of the MMP subtypes (25,30,65,163,240,241,258,273,277,304,329,377,440,466,514,539). The polymorphisms that have been identified thus far often affect the promoter region of the MMP gene, and thereby influence critical steps in the binding of transcription factors or the overall efficiency of transcription.…”