To evaluate the nucleocytoplasmic distribution of p53 in HNSCC cell lines, methanol-fixed cells were stained for p53 (green) and counterstained with DAPI (blue) to visualize the nucleus. Nuclear p53 signal is detectable in all cell lines shown since all expressed p53 proteins with intact nuclear localization signal (NLS). HNSCC cell lines with intact nuclear p53 signal were found to be more sensitive to cisplatin treatment than such with loss of nuclear p53 signal. Confocal laser scanning microscopy, original magnification, x100. For further details, please see Mandic et al. in this issue.