RAD51 and head and neck squamous cell carcinoma: Whilst not previously shown in HNSCC, a study in pancreatic cancer cells showed pre-treatment with the Chk1 inhibitor AZD7762 resulted in significantly less RAD51 positive cells following irradiation [30], which was further supported by the DR-GFP reporter assay that demonstrated significantly less active HR repair of induced DSBs in the presence of AZD7762.