APOBEC3B and head and neck squamous cell carcinoma: APOBECs are a family of enzymes that catalyze the deamination of cytosine bases, APOBEC3B expression is higher in cell lines [10] and HNSCC tumors [8] with viral infection, APOBEC activity has been found to be positively correlated with the upregulation of immune signaling pathways [9], and promoter elements and transcription factors linking HPV16 infection and APOBEC3B expression have been identified [11, 12].