Genomic imprinting and cancer.

Although we inherit two copies of all genes, except those that reside on the sex chromosomes, there is a subset of these genes in which only the paternal or maternal copy is functional. This phenomenon of monoallelic, parent-of-origin expression of genes is termed genomic imprinting. Imprinted genes are normally involved in embryonic growth and behavioral development, but occasionally they also function inappropriately as oncogenes and tumor suppressor genes. The evidence that imprinted genes play a role in carcinogenesis will be discussed in this review. Additional information about imprinted genes can be found on the Genomic Imprinting Website at: (http://www.geneimprint.com).