Expression of DNA Topoisomerase II-alpha as a Proliferating Marker in Urothelial Carcinoma of Urinary Bladder based on World Health Organization/International Society of Urological Pathology Consensus Classification: A Correlation with Expression of Ki-67

ABSTRACT

BACKGROUND: DNA topoisomerase II-alpha is linked with active cell proliferation in mammalian cells. The aim of this study was to examine the relationship between the expression of DNA topoisomerase II-alpha as a proliferating marker, and the expression of Ki-67 and apoptosis in urothelial carcinoma of urinary bladder based on World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification. METHODS: 73 urothelial carcinomas of the urinary bladder after transurethral resection and 25 carcinomas after radical cystectomy were investigated for histologic grading based on WHO and WHO/ISUP consensus classification. Formalin fixed, paraffin embedded tissue of 98 specimens from 73 patients were immunohistochemically stained for DNA topoisomerase II-alpha and Ki-67, and in situ TdT-mediated dUTP-biotin nick end labeling method for evaluation of apoptotic cells was performed. For each case, a DNA topoisomerase II-alpha, Ki-67, and apoptotic indices were determined. RESULTS: The histologic grades of 73 cases based on the WHO grading system were 21.9% (16 cases) in grade 1, 65.8% (48 cases) in grade 2, and 12.3% (9 cases). 5.5% (4 cases) of papillary neoplasm of low malignant potential, 47.9% (35 cases) of urothelial carcinoma of low grade, and 46.6% (34 cases) in urothelial carcinoma of high grade were reclassified using the WHO/ISUP consensus classification. Histologic grades based on two grading systems were correlated to invasion and stage (p<0.05). DNA topoisomerase II-alpha, Ki-67, and apoptotic indices were correlated to histologic grades based on two grading system and invasion. Also, the correlation of DNA topoisomerase II-alpha and Ki-67 indices, and DNA topoisomerase II-alpha and apoptotic indices were significant, respectively. CONCLUSIONS: DNA topoisomerase II-alpha appears to be an useful marker for assessing the proliferation potential of urothelial carcinoma of in the urinary bladder.