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.
BACKGROUND:Insulin-like growth factor-1 receptor (IGF-1R), epidermal growth factor receptor (EGFR), humanepidermal 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.
Authors: J Syrios; N Diamantis; E Fergadis; L Katsaros; M Logothetis; Iota Iakovidou; E Lianos; A Grivas; A E Athanasiou Journal: Med Oncol Date: 2014-06-07 Impact factor: 3.064