Genomic stability is preserved by error-free replication, DNA repair and recombinational events.
In essence, DNA repair genes play a key role in such stability. An 87 bp deletion in the coding sequence of polb occurs in tumors. This deletion encodes amino acid residues 208-236 in the catalytic domain of the polb protein. Examining a mismatch repair gene, hMSH2, we have found variant forms of hMSH2 in breast tumors. This is the first report that hMSH2 variants are associated with breast cancer.