 Two or three epigenetic deficiencies in expression of ERCC1, XPF and/or PMS2 were found to occur simultaneously in the majority of the 49 colon cancers evaluated.Some of these DNA repair deficiencies can be caused by epimutations in microRNAs as summarized in the MicroRNA article section titled miRNA, DNA repair and cancer.Cancers usually result from disruption of a tumor repressor or dysregulation of an oncogene.