MSH2 is a 'DNA repair' gene that helps to protect against bowel, uterine and ovarian cancer.
Everyone has two MSH2 genes (one from their mother, and one from their father). If one of the genes is not working, this is known as having a faulty MSH2 gene, or having a MSH2 mutation. Certain faults in a nearby gene called EPCAM can also cause the MSH2 gene not to work. This causes a similar chance of developing cancer as having a faulty MHS2 gene.