PARP1 and head and neck squamous cell carcinoma: Preclinical data from HNSCC cell lines and mouse models have demonstrated that NSB1 gene downregulation is associated with disruption of HR and increased sensitivity to PARP inhibitors; in addition, co-inhibition of the MRN complex and PARP has been shown to induce DSB accumulation, telomere shortening, and ultimately cell death [167].