In a previous study of the same group, ceramide-dependent lethal mitophagy was initially suggested as a novel form of cell death in HPV− HNSCC, and HPV16 E7 was identified as an activator of E2F5 (E2F Transcription Factor 5), which acts as a scaffold protein for DRP1 (Dynamin-related protein 1), an upstream inducer of ceramide-dependent lethal mitophagy (Sentelle et al. 2012). This evidence concerns the gene E2F5 and head and neck squamous cell carcinoma.