Molecular and Functional Key Features and Oncogenic Drivers in Thymic Carcinomas

Simple Summary Thymic carcinomas are the most aggressive thymic epithelial tumors. While thymic carcinomas do not have a single specific cause, various aspects of their growth have been evaluated at the molecular level. In this review, we organize the recent findings according to what have been defined as the hallmarks of cancer. The identification of the molecular alterations that drive the growth of these tumors is crucial for the development of effective target therapies. Inactivation of CDKN2A, TP53, and CDKN2B by somatic mutation or deletion is most common in thymic carcinomas. In advanced tumors, mutations in genes that regulate epigenetic and chromatin remodeling can occur. On the contrary, mutations in tyrosine kinase receptors and other oncogenes are only occasional, with those of KIT being the most common and present in only 10% of thymic carcinomas. Thymic carcinomas present an enhanced and aberrant vasculature that has been targeted in clinical trials with promising results. Additionally, thymic carcinomas evade the control of the immune system, with some tumors showing a response to immune checkpoint inhibitors.Abstract Thymic epithelial tumors, comprising thymic carcinomas and thymomas, are rare neoplasms. They differ in histology, prognosis, and association with autoimmune diseases such as myasthenia gravis. Thymomas, but not thymic carcinomas, often harbor GTF2I mutations. Mutations of CDKN2A, TP53, and CDKN2B are the most common thymic carcinomas. The acquisition of mutations in genes that control chromatin modifications and epigenetic regulation occurs in the advanced stages of thymic carcinomas. Anti-angiogenic drugs and immune checkpoint inhibitors targeting the PD-1/PD-L1 axis have shown promising results for the treatment of unresectable tumors. Since thymic carcinomas are frankly aggressive tumors, this report presents insights into their oncogenic drivers, categorized under the established hallmarks of cancer.