In addition to being correlated with microsatellite instability, Kirsten Rat Sarcoma Virus (KRAS), -catenin, and/or human MutL Homolog 1 (hMLH1)/MutS Homolog 2 (MSH2) mutations, type I endometrial carcinoma is directly linked to prolonged exposure to high estrogen levels. This evidence concerns the gene MSH2 and endometrial carcinoma.