Protein expression and gene copy number changes of receptor tyrosine kinase in thymomas and thymic carcinomas

T. Mimae, K. Tsuta, T. Kondo, H. Nitta, T. M. Grogan, M. Okada, H. Asamura, H. Tsuda

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Background: Insulin-like growth factor-1 receptor (IGF-1R), epidermal growth factor receptor (EGFR), human epidermal growth factor receptor-type 2 (HER2), and c-Met are members of the receptor tyrosine kinases (RTKs). The associations between the RTK status [protein expression and gene copy number (GCN)] and patient characteristics and between the RTK status and prognosis remain undetermined. Materials and methods: The study included 140 patients who underwent surgery for thymic tumors. Protein expression was evaluated by immunohistochemistry (IHC) and GCN was evaluated by bright-field in situ hybridization (BISH). The correlations between the RTK status and clinicopathological findings were examined. Results: IGF-1R protein was frequently detected in thymic carcinoma (83.8%) and EGFR in thymic tumors (91.4%). Thirty-six and 39 tumors were BISH high for IGF-1R and EGFR, respectively: 28 and 25 exhibited high polysomy; 8 and 14 exhibited gene amplification. No tumor was positive for HER2 or c-Met by IHC and BISH. Multivariate analysis revealed that IGF-1R gene amplification (P = 0.027), thymic carcinoma histology, and higher tumor stage were significantly correlated with an adverse prognosis. Conclusions: Thymic epithelial tumors frequently express IGF-1R and/or EGFR proteins. IGF-1R gene amplification is suggested to define an unfavorable subset for thymic epithelial tumors.

Original languageEnglish
Pages (from-to)3129-3137
Number of pages9
JournalAnnals of Oncology
Issue number12
Publication statusPublished - 2012 Dec
Externally publishedYes


  • Gene copy number
  • Insulin-like-growth factor-1 receptor
  • Thymic carcinoma
  • Thymoma
  • Tyrosine kinase receptors

ASJC Scopus subject areas

  • Hematology
  • Oncology


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