Abstract: This document relates to methods and materials for assessing and/or treating mammals (e.g., humans) having endometrial cancer. For example, methods and materials for identifying endometrial cancers likely to respond to a particular cancer treatment (e.g., a platinum based cancer therapy) are provided. This document also relates to materials and methods for using one or more cancer treatments to treat a mammal (e.g., a human) identified as likely to respond to a particular cancer treatment.