Immunotherapy in the Treatment of Undifferentiated Pleomorphic Sarcoma and Myxofibrosarcoma. (2025)

Undifferentiated pleomorphic sarcoma (UPS) and myxofibrosarcoma (MFS) are among the most common adult soft tissue sarcoma (STS) subtypes. Due to their high genetic complexity, heterogeneity, and lack of specific genetic alterations, no consistent molecular targets for targeted therapy have been identified for UPS and MFS. Recently, immune checkpoint inhibition (ICI) has emerged as a promising treatment modality for UPS and MFS. However, the efficacy of ICI in UPS and MFS remains far lower than in other cancers such as melanoma. Strategies to increase the efficacy of ICI, including selecting patients based on putative biomarkers and combining ICI with chemotherapy, targeted therapies, and/or radiation therapy, are currently in clinical development. In this review, we first summarize the cli