In addition, we included the salivary gland-derived A-253 cell line, which also bears damaging TP53 and CDKN2A mutations as a reference model, to determine if observed responses were specific to HNSCC cells or would also be observed in G1/S checkpoint-deficient cell lines of distinct lineages (Table 1 and Table S1). This evidence concerns the gene TP53 and head and neck squamous cell carcinoma.