Molecular Pathogenesis of Uterine Sarcomas: Mechanisms and Implications for Treatment.

Uterine sarcomas are rare cancers with diverse clinical, histologic, and genomic profiles. At the genetic level, they can be classified into simple and complex genomic sarcomas, exemplified by endometrial stromal sarcoma (ESS) and uterine leiomyosarcoma (uLMS), respectively. Sequencing technologies in research and clinical settings have significantly advanced the molecular understanding of these tumors. New entities characterized by distinctive morphologies and genomic alterations have expanded the category of uterine sarcomas with simple genomes beyond ESS to include variant uLMS and fibrosarcoma-like uterine sarcoma (FUS). Molecular profiling of uLMS has also uncovered possible therapeutic targets in the most common type of uterine sarcoma, where prognostication and clinical management remain challenging. This review discusses the current histologic and molecular classification of low- and high-grade ESS, FUS, and conventional and variant uLMS and explores the potential impact of the genetic alterations observed in these uterine sarcomas on treatment.