PMS2 and ovarian cancer: Moreover, for women who underwent risk-reducing bilateral salpingo-oophorectomy at the age of 25 years, the risk of developing ovarian cancer by the age of 70 years was reduced by 11% for carriers of the MLH1 variant, 17% for MSH2, 11% for MSH6, and 3% for PMS2. Similarly, the risk reduction by the age of 70 years was 9% for MLH1, 16% for MSH2, 9% for MSH6, and 3% for PMS2 among those who underwent the procedure at the age of 40 years.