p53-mutant HNSCC cell lines were sensitive to small-molecule inhibitors targeting WEE1...The WEE1 kinase inhibitor, MK-1775 had the broadest and most significant effect on cell survival in both primary and recurrent/metastasis-derived HNSCC cells, with an IC50 ranging from 220 nmol/L to 3.1 μmol/L...The IC50 for MK-1775 in p53 mutant PCI-15A and PCI-15B HNSCC cells (0.14–0.17 μmol/L)...