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Morphological and molecular characteristics of HER2 amplified urothelial bladder cancer

Tschui, J. ; Vassella, E. ; Bandi, N. ; Baumgartner, U. ; Genitsch, V. ; Rotzer, D. ; Seiler, R. ; Thalmann, G. ; Fleischmann, A.

In: Virchows Archiv, 2015, vol. 466, no. 6, p. 703-710

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    Titre
    • Morphological and molecular characteristics of HER2 amplified urothelial bladder cancer
    Auteur
    • Tschui, J.. Institute of Pathology, University of Bern, Bern, Switzerland
    • Vassella, E.. Institute of Pathology, University of Bern, Bern, Switzerland
    • Bandi, N.. Institute of Pathology, University of Bern, Bern, Switzerland
    • Baumgartner, U.. Institute of Pathology, University of Bern, Bern, Switzerland
    • Genitsch, V.. Institute of Pathology, University of Bern, Bern, Switzerland
    • Rotzer, D.. Institute of Pathology, University of Bern, Bern, Switzerland
    • Seiler, R.. Department of Urology, University Hospital of Bern, Bern, Switzerland
    • Thalmann, G.. Department of Urology, University Hospital of Bern, Bern, Switzerland
    • Fleischmann, A.. Institute of Pathology, University of Bern, Murtenstr.31, 3010, Bern, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Virchows Archiv, 2015, vol. 466, no. 6, p. 703-710. Springer Berlin Heidelberg
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:331532
    Summary
    Several (pre-) clinical trials are currently investigating the benefit of HER2-targeted therapy in urothelial bladder cancer (UBC). Patients with HER2 amplified UBC could potentially profit from these therapies. However, little is known about histomorphology, HER2 protein expression patterns and occurrence of alterations in the HER2 gene in their tumors. Among 150 metastasizing primary UBC, 13 HER2 amplified tumors were identified. Their histopathological features were compared with 13 matched, non-amplified UBC. HER2 protein expression was determined by immunohistochemistry. The 26 tumors were screened for mutations in exons 19 and 20 of the HER2 gene. UBC with HER2 amplification presented with a broad variety of histological variants (median 2 vs. 1), frequently featured micropapillary tumor components (77% vs. 8%) and demonstrated a high amount of tumor associated inflammation. Immunohistochemically, 10 of 13 (77%) HER2 amplified tumors were strongly HER2 protein positive. Three tumors (23%) were scored as HER2 negative. One of the HER2 amplified tumors harbored a D769N mutation in exon 19 of the HER2 gene; all other tested tumors were wild type. In conclusion, HER2 amplified UBC feature specific morphological characteristics. They frequently express the HER2 protein diffusely and are, therefore, promising candidates for HER2 targeted therapies. The detection of mutations at the HER2 locus might add new aspects to molecular testing of UBC.