Survivin expression in human chondrosarcoma. Immunohistochemistry and immunoblot for survivin (red staining) from human chondrosarcoma specimens. A: Low-power image of human high-grade chondrosarcoma displays strong cellular expression of survivin protein. B: High-power magnification reveals the predominantly cytoplasmic staining, although strong nuclear signals are detectable. C and D: Other specimen of a grade III chondrosarcoma stained with monoclonal antibody, shows a similar pattern of staining. E: Strong survivin signal in a tumor cell displaying a mitotic figure (arrow). F: To verify the expression of survivin in human chondrosarcoma, immunoblots were performed from 3 high grade chondrosarcoma lysates (Patient Nr. 5, 7, 10). As control for the correct molecular weight, in vitro-transcribed and -translated (IVTT) recombinant survivin protein, derived from the full-length human cDNA was loaded. Furthermore, lysates from adult human cartilage served as a negative control. Total protein loaded was 1 μg for recombinant human survivin, 60 μg for chondrosarcoma and cartilage lysates. For A, B and E the polyclonal rabbit anti-survivin antibody AF886 was used. For C and D the monoclonal mouse anti-survivin antibody clone 32.1 was used. Original magnifications: 200× (A and C) and 400× (B and D) and 600× (E).