Histone methyltransferases in tumor suppression.

It is well established that human cancer can be caused by mutations in the molecular pathways that control cell proliferation, differentiation, and survival. Familial cancer syndromes are associated with mutations in tumor susceptibility genes. However, sporadic common cancers are primarily linked to environmental factors that often lack any obvious mutagens. This raises the question whether mutation is necessary for environmental carcinogens to cause cancer. Histone methyltransferases function to control mitotic inheritance of cell fate and gene expression patterns and can turn environmental effects into heritable changes in cell phenotypes. The discovery of tumor suppressor function for these enzymes has important implications for an epigenetic pathway of cancer.