Cancer cells show characteristic alterations in DNA methylation patterns. Aberrant CpG methylation of specificpromoters results in inactivation of tumor suppressor genes and therefore plays an important role in carcinogenesis. Thep53-regulated gene 14-3-3σ undergoes frequent epigenetic silencing in several types of cancer, including carcinoma ofthe breast, prostate, and skin, suggesting that the loss of 14-3-3σ expression may be causally involved in tumor progression.Functional studies demonstrated that 14-3-3σ is involved in cell-cycle control and prevents the accumulation of chro-mosomal damage. The recent identification of novel 14-3-3σ-associated proteins by a targeted proteomics approachimplies that 14-3-3σ regulates diverse cellular processes, which may become deregulated after silencing of 14-3-3σexpression in cancer cells.