Analyzed the literature devoted to the changes in the expression of the RAS proteins of cancer cells. A brief review of protein expression dynamics PAC in malignant tumors and the possible role of epigenetic mechanisms in these processes. Through research epigenetic mechanisms state for cancer have been developed principally new techniques for their correction, based on the use of selective regulators systems covalent modification-histone proteins (for example, deacetylase inhibitor) and microRNA synthesis technologies. Literature data show promising pharmacological correction epigenetic modification of chromatin in the treatment of cancer.