The importance of this interdependence of epigenetic DNA modifications (methylation and deacetylation) and condensed chromatin structure is confirmed by results of research with colon cancer cells treated with HDAC inhibitors, where an increase in activity of genes silenced by epigenetic modification (for example, MLH1, TIMP-3 and CDKN2A) has been possible only in the presence of DNA methyltransferase inhibitors [40]. This evidence concerns the gene HDAC9 and malignant colon neoplasm.