Hereditary NonPolyposis Colorectal Cancer (HNPCC) is an inherited condition, resulting from a mutation in the MSH2 gene, which encodes a protein essential for the DNA mismatch repair mechanism (MMR). Defects in MMR cause higher mutation rates leading to uncontrolled cell growth and tumor formation. However, it is unclear which mutations such as Single Nucleotide Polymorphisms (SNP) in MSH2 leads to dysfunctional MSH2. Some mutations could maintain a normal function of MSH2, while others can impair its function. In this study, we compared the mutation rates of yeast, our model organism, with a wild-type MSH2 gene, a mutated msh2 gene (G693D), or transformed with an empty vector, using a yeast FluoroOrotic Acid assay. If the mutation impairs the function of MSH2, the mutation rate of yeast should increase and can be pathogenic. If the mutation does not impair the function of MSH2, the mutation rate of yeast should remain as low as the wild-type yeast, and can be considered pseudo-wild-type. We predict that the mutation will impair the function of MSH2, increasing the mutation rate compared to the wild-type. This research may help determine whether an individual carrying a particular SNP has a higher probability of developing HNPCC.
