This domain also contains a breast cancer susceptibility gene1 C-terminus (BRCT) motif, a protein-protein interaction motif, which is commonly found in proteins involved in DNA repair and control of the cell cycle [15], the PARP1 BRCT domain is required for the interaction between PARP1 with several partner proteins, including X-ray repair cross complement gene 1(XRCC1) [16] and histones [17]. The gene discussed is PARP1; the disease is cancer.