PTPA and carcinoma: However, on the other hand, PP2A has been described as a negative regulator of PRMT1 in a hepatocyte-derived carcinoma cell line36,37, taking these data into consideration, new studies should be performed to elucidate the involvement of PP2A on the methylation of BRCA1 after IR in breast cancer and other tumor cell types, since it might be cell-dependent.