DNA methylation and acetylation of histone proteins represent two global mechanisms controlling the gene
expression. DNA methylation profiles alter during the development of the organism and during progression of
neoplasia. Three types of alterations of the DNA methylation profiles were observed in the tumor cells: hypo-
methylation, hypermethylation and the loss of imprinting. Beside the intra-gene mutation and the heterozygosity
absence, DNA methylation can be understood as the third mechanism of tumor-suppressor gene inactivation in the
genesis of neoplasia. Our review article brings recent findings and hypotheses on the role of DNA methylation in
the carcinogenesis and its possible application in the diagnostics and therapy of the malignant proliferation.
DNA methylation, CpG islands, tumor-suppressor genes, modulation of gene expression, carcinoge-