p53 relocation after Nutlin-3a treatment. (A) Representative p53 localization patterns (arrows) in primary CLL cells from patient no. 5 (nuclear accumulation) and no. 8 (cytoplasmic accumulation), which were treated with 5 μM Nutlin-3a for 6 hours. Cells were stained for p53 (green) and mitochondrial marker protein cytochrome c oxidase IV (red) and visualized by confocal microscopy. Nuclei were counterstained with DAPI (blue). (B) Preferential translocation of cytoplasmic p53 to mitochondria in CLL cells. Localization of p53 to mitochondria is indicated by the yellow-orange color in the merged image (arrowheads).