Understanding MSI/MMR


Microsatellites can be found throughout the human genome and are short tandem repeats the are made up of one to six base pairs. They are prone to errors and rely on mismatch repair (MMR) proteins to correct them. High microsatellite instability (MSI-H) and deficiency in MMR genes lead to a lack of protein expression in MLH1, MSH2, MSH6, or PMS2. A decrease in the ability to repair DNA leads to an increased number of variants in DNA, leading to genomic instability.

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