Distinct genomic subgroups and mutational patterns in undifferentiated/dedifferentiated endometrial carcinoma
Endometrial cancer represents a significant global health challenge, with undifferentiated and dedifferentiated endometrial carcinoma (UDEC) being a particularly aggressive subset. We employed whole-exome sequencing (WES) to comprehensively characterize the molecular landscape of 29 UDECs in a single institution cohort. We analyzed driver mutations, molecular subgroups, SWI/SNF complex, DNA mismatch repair (MMR) pathways, and somatic copy number alterations (SCNAs). We identified 5 (17%) ultramutated tumors, 14 (48%) DNA mismatch repair (MMR)-deficient tumors, and 10 (35%) mutation-low tumors in this cohort. Mutations in the SWI/SNF family and other driver genes are common, including PTEN, ARID1A, KMT2B, ARID1B, SMARCA4, and PIK3CA. Genomic inactivation of SWI/SNF complex genes occurred in 19 of 29 (66%) of cases, highlighting the frequent chromatin remodeling dysfunction in UDEC. We observed frequent homopolymer mutations in UDECs with MMR deficiency, with RPL22 Our analysis revealed distinct architectures and actionable alterations in UDEC. The identification of molecular subgroups provides a promising framework for prognostic stratification. Collectively, our findings not only advance our understanding of UDEC biology but also illuminate potential translational applications.