DNA sequence variations contribute to inter-individual variability in susceptibility to and/or severity of common diseases such as cancer, diabetes, and asthma. About 90% of all sequence variations in the human genome are single nucleotide polymorphisms. Each single nucleotide polymorphism arises from a single nucleotide substitution, resulting in the presence of two alleles which differ by one base pair of DNA. The second most common form of DNA sequence variation is microsatellite polymorphism, which is also known as short tandem repeat polymorphism. A microsatellite is a run of tandem repeats of a short DNA sequence, usually 1–4 base pairs. A microsatellite polymorphism can be di-allelic or multi-allelic, with the different alleles differing in the number of repeat units, and hence in length. It is likely that only a very small percentage of DNA sequence variations in the human genome are functionally important, exerting effects on gene expression or function. A DNA sequence variant that is functionally neutral can still be found to be associated with disease susceptibility, arising from linkage disequilibrium with a functional variant located on the same chromosome. Identification of genetic variants that contribute to disease susceptibility and/or severity can provide understanding of the molecular basis of the disease, could have diagnostic and prognostic value, and may provide useful molecular targets for developing novel therapeutics. There is evidence suggesting that polymorphisms in certain matrix metalloproteinase (MMP) genes could influence cancer susceptibility and/or prognosis. This chapter will highlight some of these findings, focusing on MMP1, MMP2, MMP3, MMP9, and MMP12.
KeywordsNeck Squamous Cell Carcinoma Oral Squamous Cell Carcinoma Gastric Cardia Adenocarcinoma Microsatellite Polymorphism Oesophageal Squamous Cell Carcinoma
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