Abstract

Biological methylation is mediated by a ternary enzyme complex consisting of methionine adenosyl-transferase (MAT)-methyltransferase (MT)-S-adenosylhomocysteine hydrolase (SAHH). SAHH is a steroid receptor. Steroid factors generated by growth signals play dominant roles on the regulation of normal MEs. Cancer MEs are abnormal due to association of MAT with telomerase which becomes a dominant factor to regulate cancer MEs. The association of cancer MEs with telomerase locks cancer MEs in an exceptionally stable and active state so that hypomethylation of DNA necessary for the activation of differentiation related genes cannot take place. Blockade of differentiation attributable to abnormal MEs is a very important issue of cancer. Because of the blockade of differentiation, cancer cells keep on replicating, allowing oncogenes and suppressor genes to attract a great deal of attention in the field of cancer. Oncogenes and suppressor genes are cell cycle regulatory genes. They have important roles to play when cells are in cell cycle replicating. But they have no role to play when replicating cells are diverted to undergo terminal differentiation (TD). So, a stroke to destabilize abnormal MEs can wipe out all damages generated by oncogenes and suppressor genes.