MAPK8 and head and neck squamous cell carcinoma: While basal clonogenic 3D HNSCC cell survival remained unaffected (SAS, UTSCC14) or only slightly reduced (UTSCC15, FaDu) by p38 and JNK inhibitors (Figure 4A), a decrease in plating efficiency was observed upon ERK inhibition in all cell lines ranging between 33% (FaDu) and 81% (UTSCC14) relative to DMSO (Figure 4B and Figure S2C).