[971] Her2 Amplification Is Associated with a High Risk of Progression in Non-Muscle-Invasive Bladder Cancer

Chin-Chen Pan. Taipei Veterans General Hospital, Taipei, Taiwan

Background: Her2/neu amplification and overexpression have been studied mainly in invasive and metastatic bladder cancers, but its significance in non-muscle invasive bladder cancer (NMIBC) has not been substantially investigated. The study was conducted to evaluate the prognostic value of Her2 amplification in NMIBC.
Design: Immunohistochemistry for neu and fluorescence in situ hybridization (FISH) using Her2/CEP17 probe (PathVysion) were performed on 8 cases of papillary urothelial neoplasm of low malignant potential (PUNLMP), 108 cases of low-grade papillary urothelial carcinoma (LPUC) and 169 cases of high-grade papillary urothelial carcinoma (HPUC). The immunoreactivity for neu was assessed by the percentage of tumor cells showing complete membranous positivity. Amplification was defined following the ASCO/CAP guideline (Her2/CEP 17 ratio >2.2). The status of Her2 amplification was correlated to progression of detrusor muscle invasion (progression from Ta/T1 to T2-4, metastasis or cancer-specific mortality).
Results: None of the PUNLMPs and LPUCs showed Her2 amplification. Fifteen (8.9%) of HPUCs showed Her2 amplification. Eleven (73.3%) of Her2-positive HPUCs progressed into muscle-invasive or metastatic disease. The cumulative incidence of progression at 5 years was 80.9% in Her2-positive HPUCs, as opposed to 40.1%, 14.8% and 2.2% in T1 Her2-negative HPUC, Ta Her2-negative HPUC, and LPUC/PUNLMP, respectively (p<0.0001). When overexpression of neu was defined using a cut-point of 50%, the concordance rate between immunohistochemistry and FISH was 100%.
Conclusions: Her2 amplification and overexpression can discern a subset of NMIBC with high risk for progression. These patients may be eligible for target therapy if the tumor progressed.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 135, Wednesday Afternoon

 

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