A recent study has highlighted the importance of PARP-1 in regulating the repair of complex DNA damage (CDD) induced by high-LET radiation by demonstrating that high-LET proton-induced CDD and concomitant inhibition of PARP-1 (with olaparib) leads to cell death in the HPV(−) HNSCC cell line UMSCC74A [209]. The gene discussed is PARP1; the disease is head and neck squamous cell carcinoma.