The Her2/neu oncogene, which indicates a poor prognosis, is expressed in 20% of endometrioid and serous carcinomas. CTNNB1 (beta-catenin; a transcription gene) mutations are found in 14–44% of endometrial cancers and may indicate a good prognosis, but the data is unclear. Beta-catenin mutations are commonly found in endometrial cancers with squamous cells. FGFR2 mutations are found in approximately 10% of endometrial cancers, and their prognostic significance is unclear. SPOP is another tumor suppressor gene found to be mutated in some cases of endometrial cancer: 9% of clear cell endometrial carcinomas and 8% of serous endometrial carcinomas have mutations in this gene.Type I and Type II cancers (explained below) tend to have different mutations involved. ARID1A, which often carries a point mutation in Type I endometrial cancer, is also mutated in 26% of clear cell carcinomas of the endometrium, and 18% of serous carcinomas. Epigenetic silencing and point mutations of several genes are commonly found in Type I endometrial cancer. Mutations in tumor suppressor genes are common in Type II endometrial cancer. PIK3CA is commonly mutated in both Type I and Type II cancers. In women with Lynch syndrome-associated endometrial cancer, microsatellite instability is common.Development of an endometrial hyperplasia (overgrowth of endometrial cells) is a significant risk factor because hyperplasias can and often do develop into adenocarcinoma, though cancer can develop without the presence of a hyperplasia. Within ten years, 8–30% of atypical endometrial hyperplasias develop into cancer, whereas 1–3% of non-atypical hyperplasias do so. An atypical hyperplasia is one with visible abnormalities in the nuclei.
Northern Europe, Eastern Europe, and North America have the highest rates of endometrial cancer, whereas Africa and West Asia have the lowest rates. Asia saw 41% of the worlds endometrial cancer diagnoses in 2012, whereas Northern Europe, Eastern Europe, and North America together comprised 48% of diagnoses. Unlike most cancers, the number of new cases has risen in recent years, including an increase of over 40% in the United Kingdom between 1993 and 2013. Some of this rise may be due to the increase in obesity rates in developed countries, increasing life expectancies, and lower birth rates. The average lifetime risk for endometrial cancer is approximately 2–3% in people with uteruses. In the UK, approximately 7,400 cases are diagnosed annually, and in the EU, approximately 88,000.Endometrial cancer appears most frequently during perimenopause (the period just before, just after, and during menopause), between the ages of 50 and 65; overall, 75% of endometrial cancer occurs after menopause. Women younger than 40 make up 5% of endometrial cancer cases and 10–15% of cases occur in women under 50 years of age. This age group is at risk for developing ovarian cancer at the same time. The worldwide median age of diagnosis is 63 years of age; in the United States, the average age of diagnosis is 60 years of age. White American women are at higher risk for endometrial cancer than black American women, with a 2.88% and 1.69% lifetime risk respectively.