Author(s): Chen PC, Yu HJ, Chang YH, Pan CC
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Abstract BACKGROUND: Several studies have employed immunohistochemistry to detect Her2/neu overexpression in urothelial carcinomas, yielding a tremendous range of positive expression rates. Few studies have examined Her2 status in non-muscle invasive bladder cancer (NMIBC) using fluorescence in situ hybridisation (FISH). AIM: To evaluate Her2 amplification in NMIBC (Ta/T1), to correlate the findings with recurrence and progression, and compare the Her2 status between primary and progressive tumours. METHODS: FISH and immunohistochemistry for Her2/neu were performed on tissue arrays consisting of 36 papillary urothelial neoplasms of low malignant potential (PUNLMPs), 190 low grade urothelial carcinomas (LG-UCs) and 178 high grade urothelial carcinomas (HG-UCs). 32 cases with specimens of both primary and progressive tumours (from Ta/T1 to T2-4) were included for comparative analyses. RESULTS: 16 HG-UCs (9.0\%) showed Her2 gene amplification while none of the PUNLMPs and LG-UCs showed this aberration. There was 100\% concordance in the status of Her2 amplification between primary and progressive lesions. Immunohistochemistry and FISH results were in closest agreement when overexpression was defined as 50\% of tumour cells showing immunoreactivity. The cumulative incidences of recurrence and progression in Her2-amplified HG-UC were significantly higher than in those without amplification. CONCLUSIONS: A subset of high-grade NMIBCs contain Her2 amplification and are associated with markedly aggressive behaviour. Her2 diagnostics are valuable for distinguishing patients who require diligent surveillance and would potentially benefit from anti-Her2 therapies.
This article was published in J Clin Pathol
and referenced in Journal of Cytology & Histology