MRE11, a DNA repair gene, is under-expressed in breast cancers, and cancers are very often deficient in expression of one or more DNA repair genes.
This gene encodes a nuclear protein involved in homologous recombination, telomere length maintenance, and DNA double-strand break repair. MRE11 is over-expressed in breast cancers. Cancers are very often deficient in expression of one or more DNA repair genes, but over-expression of a DNA repair gene is less usual in cancer. 
