SETD2 protein is a histone methyltransferase that is specific for lysine-36 of histone H3, and methylation of this residue is associated with active chromatin. The trimethylation of lysine-36 of histone H3 （H3K36me3） is required in human cells for homologous recombinational repair and genome stability. Depletion of SETD2 increases the frequency of deletion mutations that arise by the alternative DNA repair process of microhomology-mediated end joining. The SETD2 gene is located on the short arm of chromosome 3 and has been shown to play a tumour suppressor role in human cancer.