Expression of apoptosis-related markers and HER-2/neu in thymic epithelial tumours

Chin Chen Pan, P. C H Chen, L. S. Wang, J. Y. Lee, H. Chiang

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Aims: To correlate the expression of a series of apoptotic and oncogene markers (including p53, Bcl-2, BAX, Bcl-XL, p21WAF.1/CIP1, cyclin D1, HER-2/neu) in thymic epithelial tumours with histological type, stage and resectability and to determine whether the information on HER-2/neu would be valuable in identifying patients who are eligible for anti-HER-2/neu treatment. Methods and results: Immunohistochemical stains were performed on 16 cases of non-neoplastic thymus, 63 thymomas and 17 thymic carcinomas. Fluorescence in-situ hybridization (FISH) for HER2 was performed to validate the gene amplification. Eighteen thymomas were positive for p53 and 14 of them were low-expressors, with positive cells below 10%. All thymic carcinomas revealed over-expression of p53 with positive cells either between 10% and 50% or >50%. The expression of p53 correlated with histological type and stage in thymoma. In both thymoma and thymic carcinoma, there was a statistically significant correlation between p53 status and resectability, with low expressors having a higher likelihood of being resectable. Thymic carcinomas, regardless of the histological subtypes, uniformly expressed Bcl-2, while thymomas showed no or only weak cytoplasmic immunoreactivity. Most thymomas and thymic carcinomas were negative for Bcl-XL, p21WAF.1/CIP1 and cyclin D1. The expression of BAX was inconsistent among different histological types. Nine thymic carcinomas revealed membranous positivity for HER-2/neu. but no HER2 gene amplification could be demonstrated by FISH in any of the cases. Conclusions: p53 and Bcl-2 are more implicated in the development of thymic carcinoma than thymoma. The higher level of p53 expression and the strong immunopositive pattern of Bcl-2 in thymic carcinomas have potential value in the differential diagnosis and prediction of aggressiveness and resectability. On account of the absence of HER2 amplification, patients would probably not benefit from anti-HER-2/neu treatment.

Original languageEnglish
Pages (from-to)165-172
Number of pages8
JournalHistopathology
Volume43
Issue number2
DOIs
Publication statusPublished - Aug 1 2003
Externally publishedYes

Keywords

  • Apoptosis
  • Bcl-2
  • Fluorescence in-situ hybridization
  • HER-2/neu
  • Immunohistochemistry
  • p53
  • Thymic carcinoma
  • Thymoma

ASJC Scopus subject areas

  • Cell Biology
  • Anatomy
  • Pathology and Forensic Medicine

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