Type I endometrial carcinoma is directly associated with long-term exposure to high estrogen levels and correlates with Phosphatase and TENsin homolog (PTEN) inactivation by mutation, microsatellite instability, as well as mutations of Kirsten RAt Sarcoma virus (KRAS), β-catenin, and/or human MutL Homolog 1 (hMLH1)/MutS Homolog 2 (MSH2). Here, MLH1 is linked to endometrial carcinoma.