TP53 and head and neck squamous cell carcinoma: Although our sample size was small, these findings are consistent with larger studies of HNSCC which found that the most frequent mutations were in TP53 (72 %), FAT1 (23 %), CDKN2A (22 %), PIK3CA (21 %), NOTCH1 (19 %), KMT2D (18 %), NSD1 (10 %), CASP8 (9 %) [18], [19], [20], [21], [22], [23], [24], [25].