APOBEC3B and head and neck squamous cell carcinoma: Importantly, levels of human A3B protein in the nuclei of murine tumor cells approximate the upper amounts observed in the nuclei of human tumor cells (e.g., IHC for representative head and neck squamous cell carcinomas in Figure 3D, with comparison to additional murine tumor and healthy tissues in Figure 3E and quantification in Figure 3F; additional head and neck squamous cell carcinoma [HNSCC] information in Table S2).