APEX2 and neoplasm: High tumor grade was associated with higher methylation of RAD51C and TREX1 and lower methylation of OBFC2B. Significant associations of lower methylation profiles of APEX2, ERCC2, FANCB, RAD51C, HUS1, and MSH5 with HGSC subtype and, on the opposite, higher methylation of MPG with the HGSC subtype were discovered (Table 3).