Previous studies have already demonstrated IR-dependent induction of MEK/ERK in established HNSCC cell lines and an ex vivo tissue culture model.4,12,13 Targeting ERK1/2 kinase provides potential therapeutic opportunities for a broad spectrum of cancers.14 Therapy response is impacted by a pronounced intra-tumorigenic heterogeneity in HNSCC. Here, MAPK1 is linked to head and neck squamous cell carcinoma.