A Pilot Study of Microsatellite Instability and Endometrial Cancer Survival in White and African American Women

Endometrial cancer is the most commonly diagnosed gynecologic malignancy in the United States and can be classified on the basis of various pathologic, molecular, and genetic features, including microsatellite instability (MSI). As MSI is generally associated with a more favorable outcome in colorectal cancers, it is feasible that microsatellite instability may also influence endometrial cancer survival. We examined MSI and survival in 45 African American and 31 white women diagnosed with endometrial cancer at a large, urban cancer center. Fifty-five tumors were classified as type I and 21 tumors were classified as type II. Unconditional logistic regression models found that microsatellite stable tumors were more frequently observed in white women compared with African American women (odds ratio, 8.61; 95% confidence interval, 1.01-73.69). Type I tumors with MSI were not found to be significantly associated with smoking status, tumor stage, or age. Only one type II tumor was classified as MSI. Neither race nor MSI status was a predictor of death from all causes or only endometrial cancer-related deaths were considered in univariate and multivariate survival models. The potential significance of a larger proportion of MSI tumors found in African American women with type I endometrial cancer should be assessed in a larger prospective study.