The present study was performed to investigate if MLH1, MGMT, CDKN2A, and RASSF1A genes are hypermethylated in TAMG-associated thymomas with respect to the normal residual thymuses or circulating lymphocytes of the same patients, and if the methylation patterns of TAMG-associated thymomas exhibit differences in relation to age, gender, and TAMG clinical features. Here, RASSF1 is linked to thymoma.