Emerging biomarkers for checkpoint inhibitors in thymic epithelial tumors

Despite recent advances in the treatment of thymic epithelial tumors the only curative intervention remains surgical resection. Recent studies have evaluated novel treatments in patients with refractory TET including with targeted therapies and immune checkpoint inhibitors (1,2). Although several studies have evaluated the expression of immune markers such as programmed death-1 (PD-1) and its ligand PD-L1, there is no clear consensus on the role of these biomarkers in TET. We thank Dr.’s Guleria and Jain as well as Dr.’s Sekine, Aida, and Suzuki for their interest in our study evaluating PD-L1 and PD-1 expression in thymic epithelial tumors (TETs) (3). Both teams have raised many interesting issues which we believe are worthy of further discussion and may be used to help guide future research in these rare entities.