Consistent with previous findings, we observed that ERK inactivation and S6K T389 dephosphorylation in G9a-inhibited cells in HNSCC (Figure 4A and Additional file 2: Figure S1), implying that G9a may activate ERK-TSC-mTOR signaling during HNSCC cell growth. This evidence concerns the gene TSC1 and head and neck squamous cell carcinoma.