Status of Her2 over expression in muscle invasive urothelial bladder carcinoma: Report of 21 cases

BACKGROUND: Invasive urothelial bladder carcinomas have a poor prognosis even with cystectomy and chemotherapy. A high number of these patients have Her2 overexpression. The goal of this study is to assess the Her2 status in muscle invasive urothelial bladder carcinoma, to evaluation heterogeneity and discordance with metastases. PATIENTS AND METHODS: We retrospectively analyzed 21 specimens of transurethral resection or cystectomy in patients with invasive urothelial bladder carcinoma. We selected one representative section from primary tumors and metastases for immunohistochemistry analysis. Staining was evaluated according to the same criteria of breast cancer. A chromogenic in situ hybridization (CISH) was performed in case of 2+ score or in heterogeneous samples. RESULTS: Median age of our patients was 62 years. Intratumoral heterogeneity was observed in 2 cases (less than 1%). One case showed a Her2 3+ score (high grade, pT2 stage) and 3 cases showed a 2+ score (all low grades, stage T2, T4, M1, respectively). Two metastatic lymph nodes scored 1+ for the first (primary 1+) and 2+ for the second (primary 1+). Two cases showed CISH gene amplification. The first one scored 2+ and had area of 3+ score. The second one scored 1+ and had area with 2+ score. Four patients died from disease, one of them had Her2 3+ score. CONCLUSION: Her2 overexpression can be observed in muscle invasive urothelial bladder carcinoma in an important number of patients. Evaluation criteria must be standardized, especially with heterogeneous cases. Metastases tests can also readdress the expression of Her2, which gives the patient a supplementary therapeutic tool.