As with previous studies4–7, the mutation analyses revealed a small set of genes (TP53, KMT2D CDKN2A, PIK3CA, NOTCH1, and FAT1) as the most common targets for likely deleterious sequence mutations in immortal PPOL and HNSCC cell lines (Fig. 1). Here, PIK3CA is linked to head and neck squamous cell carcinoma.