SMYD3 and head and neck squamous cell carcinoma: To evaluate whether SMYD3 KO impairs the growth rate of HPV-negative HNSCC cells in vivo in an immunodeficient environment, parental HN-6 cells and two SMYD3 KO cell lines (5–2, 5–11) were implanted in the flank of NSG mice, and tumor growth was assessed.