The impact of PD-901 in combination with cetuximab and fractionated irradiation on FaDu and Cal27 was also assessed by CFAs, which showed that administration of the MEK inhibitor strongly facilitated the treatment efficacy of cetuximab and (or) fractionated irradiation in HNSCC cell lines (Supplementary Fig. S1). This evidence concerns the gene MAP2K7 and head and neck squamous cell carcinoma.