Epigenetic defects in DNA repair genes are frequent in cancers. In the table, multiple cancers were evaluated for reduced or absent expression of the DNA repair gene of interest, and the frequency shown is the frequency with which the cancers had an epigenetic deficiency of gene expression. Such epigenetic deficiencies likely arise early in carcinogenesis, since they are also frequently found (though at somewhat lower frequency) in the field defect surrounding the cancer from which the cancer likely arose (see Table).