Molecular and phenotypic characterization of mismatch-repair/microsatellite instability-discordant endometrial cancers

Endometrial cancer is the most common gynecologic malignancy and despite therapeutic advancements, mortality rates related to endometrial cancer are rising. The Cancer Genome Atlas (TCGA) has categorized endometrial cancers into four molecular classes. Mismatch repair (MMR) deficient endometrial cancer, one of the four molecular subclasses, accounts for 20-40% of all cases. While molecular classification can be used for prognostication and to guide therapy, there is still significant heterogeneity within each subclass. We present an evaluation of cases with heterogeneous MMR expression, using next-generation sequencing, whole transcriptome analysis, and evaluation of MMR expression at sites of disease recurrence and metastasis to characterize these tumors.