['To investigate and compare topoisomerase II-alpha expression in benign prostatic hyperplasia (BPH), prostate cancer of varying Gleason scores and hormone-insensitive prostate cancer.', 'The immunohistochemical expression of topoisomerase II-alpha antibody in the above-mentioned diagnostic categories was investigated and compared.', 'Increased expression of topoisomerase II-alpha was seen in the prostate cancers of Gleason scores 7 and 8-10 (p = 0.000) compared with prostate cancers of Gleason score 6 and BPH (p = 0.245). Statistically significant differences were found in the topoisomerase II-alpha gene expression between prostate cancers categorised by Gleason Score. Also, increased expression of topoisomerase II-alpha was seen in the known hormone-resistant prostate carcinomas compared with prostate cancers with no hormone treatment in the subgroup with Gleason scores 8-10, which approached statistical significance (p = 0.081). No statistically significant difference was observed in topoisomerase II-alpha expression between the groups with BPH and prostate carcinoma of Gleason score 6 (p = 0.245).'] Does topoisomerase II-alpha expression increase with increasing Gleason score and with hormone insensitivity in prostate carcinoma?