English

Abstract

BACKGROUND Human epidermal growth factor receptor-2 HER2 / neu, is a trans membrane tyrosine kinase receptor of epidermal growth factor receptor (EGFR) family and is involved in the pathogenesis of urinary bladder cancer. In this study we attempted to evaluate the HER2 / neu expression in urothelial carcinoma of bladder and its association with tumour grading. METHODS This was a cross sectional study with a sample size of 75. Routine 4 micrometre thick sections of formalin fixed paraffin embedded tissue blocks stained with haematoxylin & eosin were reviewed. Tumour grade was determined by using the World Health Organization (WHO) / International Society of Urological Pathologist criteria (ISUP). Immunohistochemistry was done by using HER2 / neu monoclonal antibody and its expression were observed. The membrane staining intensity and pattern were studied and scored. RESULTS In our study 75 cases of urothelial carcinoma were studied, of which 49 cases were papillary urothelial carcinoma low grade, 26 cases were papillary urothelial carcinoma high grade. Among these, 19 cases were infiltrating urothelial carcinoma. HER2 / neu positivity were observed in 27 (36 %) cases and overexpression in 8 (10 %) cases. Low grade urothelial carcinoma showed HER2 / neu positivity in 11 (22 %) cases and overexpression in 1 (2 %) case. High grade urothelial carcinoma showed HER2 / neu positivity in 16 (64 %) cases, among which 7 (28 %) cases showed overexpression. HER2 / neu positivity was seen in 13 (68 %) cases of infiltrating urothelial carcinoma with 4 (21 %) cases showing overexpression. A statistically significant difference in HER2 / neu expression was noted in high grade and invasive urothelial carcinoma compared to low grade and non-invasive urothelial carcinoma. CONCLUSIONS Urothelial carcinomas show overexpression of HER2 / neu and this over expression increases with increasing grade of tumour and muscle invasiveness. KEYWORDS Urothelial Carcinoma, HER2 / neu, Overexpression, Tumour Grade, Trastuzumab