This gene encodes a nuclear protein involved in homologous recombination, telomere length maintenance, and DNA double-strand break repair.

[7] Similarly, during meiosis in the eukaryotic protist Tetrahymena Mre11 is required for repair of DNA damages, in this case double-strand breaks,[8] by a process that likely involves homologous recombination.

These observations suggest that human MRE11 is descended from prokaryotic and protist ancestral Mre11 proteins that served a role in early processes for repairing DNA damage.

Similarly, at least 12 DNA repair genes have frequently been found to be epigenetically repressed in one or more cancers.

However, MRE11 mediated MMEJ repair is highly inaccurate, so in this case, over-expression, rather than under-expression, apparently leads to cancer.