Excessive centrosome abnormalities without ongoing numerical chromosome instability. (A) Centrosome abnormalities as detected by immunofluorescence microscopy for γ-tubulin. Arrow indicates a normal centrosome (corresponding to lower right insert). Arrowheads indicate abnormal centrosomes (arrowheads and inserts correspond counterclockwise). Both numerical abnormalities (top right insert) and structural abnormalities with excessive γ-tubulin positive material are found (top left and lower left inserts). Nuclei stained with DAPI. Scale bar indicates 10 μm. (B) Normal mitotic figure detected in H&E stained section. Scale bar indicates 10 μm. (C) Abnormal multipolar mitotic figure in H&E stained section. Scale bar indicates 10 μm. (D) Quantitation of lymphoma cells undergoing metaphase or anaphase with a normal polarity (open bars) as opposed to an abnormal polarity (black bars) detected in H&E stained sections. More than one-hundred cell division figures were analyzed. (E) Fluorescence in situ hybridization (FISH) analysis for chromosome 11 confirms diploidy of the malignant lymphoma. Nuclei stained with DAPI. Scale bar indicates 10 μm.