Expression of KSHV cyclin D. (A) Higher magnification, same nodular-stage lesion of KS as shown in Fig 2B. Note abundant signal in the cytoplasm of lesional spindle cells; fewer nuclear signals are present. (B) Same nodular-stage KS tissue hybridized with the biotinylated probe of irrelevant specificity. Hybridization signals are not detected. (C) Nodular-stage lesion of KS hybridized with the KSHV-specific probe after RNAse digestion of the tissue. Only a few nuclear signals remain. (D) Benign cutaneous hemangioma, which did not contain any labeled cells. (E) BC-3 positive control cell line showing abundant cytoplasmic and nuclear hybridization signals. (F) Non-AIDS–related cutaneous NHL, which did not contain any labeled cells. All panels, ISH with catalyzed signal amplification, DAB chromogen, hematoxylin counterstain. (A, B, C, and E) Original magnification × 660. (D and F) Original magnification × 270.