European Urology European Urology 43 (2003) 505–515 CentrosomeHyperamplificationandChromosomal InstabilityinBladderCancer K. Kawamura a,* , M. Moriyama a , N. Shiba a , M. Ozaki b , T. Tanaka a , T. Nojima c , K. Fujikawa-Yamamoto d , R. Ikeda a , K. Suzuki a a Department of Urology, Kanazawa Medical University, 1-1 Daigaku Uchinada, Ishikawa, 920-0293, Japan b Department of Human Genetics, Kanazawa Medical University, Ishikawa, Japan c Department of Pathology and Laboratory Medicine, Kanazawa Medical University, Ishikawa, Japan d Division of Basic Science, Kanazawa Medical University, Ishikawa, Japan Accepted 27 January 2003 Abstract Objective: Chromosomal instability (CIN) is a common feature of malignant tumors. Centrosome hyperamplifica- tion (CH) occurs frequently in human cancers, and may be a contributing factor in CIN. In this study, we investigated the relationship between CH and CIN in bladder cancer. Methods: Clinical samples obtained by transurethral resection from 22 patients with bladder cancer were examined (histological grade G1, 5 cases; G2, 6 cases; G3, 11 cases). CH was evaluated by immunohistochemistry using anti- pericentrin antibody. CIN was evaluated by fluorescence in situ hybridization (FISH). FISH probes for pericen- tromeric regions of chromosomes 3, 7, and 17 were hybridized to touch preparations of nuclei from frozen tissues. We also analyzed the centrosome replication cycle of bladder cancer by laser scanning cytometry (LSC). Results: Of the 22 cases examined, 18 (81.8%) had centrosome hyperamplification: CH 0, 4 cases (18.1%); CH I, 5 cases (22.7%); CH II, 5 cases (22.7%); CH III, 8 cases (36.4%). The grade of CH was directly proportional to the histological grade ( p ¼ 0:03, w 2 test). LSC analysis showed that the centrosome replication cycle was well regulated in pathologically low-grade bladder cancer, which did not have chromosomal instability. In contrast, we found marked variability of centrosomes in pathologically high-grade bladder cancer, which had chromosomal instability. CH and CIN were both detected in pathologically high-grade tumors. The grade of CH was directly proportional to the CIN grade ( p ¼ 0:0079, w 2 test). Conclusion: The results of the present study suggest that CH may be involved in CIN in bladder cancer. # 2003 Elsevier Science B.V. All rights reserved. Keywords: Bladder cancer; Centrosome hyperamplification; Chromosomal instability; Pericentrin; FISH 1. Introduction The centrosome is composed of a pair of centrioles (core components of the centrosome in animal cells) and surrounding amorphous pericentriolar material. The centrosome, a major microtubule-organizing cen- ter of animal cells, directs formation of bipolar mitotic spindles, which is essential for accurate chromosome segregation to daughter cells [1–3]. The hypothesis that the centrosome plays a key role in carcinogenesis was initially proposed by Boveri, who stated that loss of cellular polarity and increased chromosomal segrega- tion errors characteristic of cancer cells result from defects in centrosome function [4]. The centrosome duplication cycle is a highly regulated process, and abrogation of its regulatory mechanisms results in uncontrolled amplification of centrosomes. Centrosome Abbreviations: CH, centrosome hyperamplification; CIN, chromosomal instability; PBS, phosphate-buffered saline; NP-40, nonidet P-40; TBS, Tris-buffered saline; DAPI, 4 0 -diamidino 2-phenylindole; FISH, fluores- cence in situ hybridization; LSC, laser scanning cytometry * Corresponding author. Tel. þ81-76-286-2211; Fax: þ81-76-286-5516. E-mail address: kawamura@kanazawa-med.ac.jp (K. Kawamura). 0302-2838/03/$ – see front matter # 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0302-2838(03)00056-3