However, there were no significant differences in the methylation levels of repair and tumor suppressor genes such as DNA methyltransferase (MGMT) and cyclin-dependent kinase inhibitor 2A (CDKN2A) between TAMG tissues and non-myasthenia gravis thymoma tissues, suggesting that methylation abnormalities of these genes may not be key events in the pathogenesis of TAMG (36). This evidence concerns the gene CDKN2A and thymoma.