PARP1 and head and neck squamous cell carcinoma: These data are in agreement with previous reports of CAF-1/p60 and PARP-1 as markers of adverse biological behaviour in oral and head and neck squamous cell carcinomas.35,69 Moreover, we found that full-length PARP-1 increased progressively from controls to primary tumours and cancer cell lines, constituting the only detectable PARP-1 form in metastatic tissue.