The epigenetics of age-related cancers

Individuals of all ages can be detrimentally affected by cancer, albeit the disease is more prevalent in aging individuals. Epigenetic modulation is essential for normal development and becomes altered in cancer and aging. The most well-studied epigenetic elements include DNA methylation, histone modifications, miRNAs, and the binding of co-regulatory proteins such as Polycomb group and Trithorax proteins. Each of these contributors to the epigenetic landscape is subjected to aberrant events that are associated with aging and with cancer. We discuss the types of epigenetic modifications that are associated with cancers that affect the young and those that affect adults. It is known that erroneous DNA damage repair, inflammation, and proinflammatory signaling occur frequently in the elderly and that these processes can also result in aberrant epigenetic modifications. Acute lymphoblastic leukemia is one type of cancer that spans the entire lifetime from birth to the aged and demonstrates a number of age-related differences in clinical behavior. Therefore, ALL provides an excellent model to begin to decipher age-related epigenetic impacts on the disease. Finally, mechanistic scenarios are given which may explain the relationship between aging and the development of cancer, and future directions which will augment the elucidation of the complex relationship between cancer and aging are discussed.