Insulin-like growth factor-1 receptor and phosphorylated AKT-serine 473 expression in 132 resected thymomas and thymic carcinomas

Abstract

BACKGROUND: Thymic malignancies are rare tumors. The insulin-like growth factor-1 (IGF-1)/IGF-1 receptor (IGF-1R) system is involved in the development of the thymus. IGF-1R expression in thymic epithelial malignancies is unknown. METHODS: The authors investigated the expression of IGF-1R and phosphorylated AKT serine 473 (p-AKT) by using immunohistochemistry and examined the clinicopathologic correlations in a retrospective, single-institution surgical series of 132 patients with thymic epithelial malignancies. RESULTS: Earlier disease stage, less aggressive histologic types, and complete resection were significant positive prognostic factors for disease-related survival and progression-free survival, and being a woman was a better prognostic factor for disease-related survival. IGF-1R and p-AKT protein levels were expressed in 20% and 36% of thymic tumors, respectively. Both markers were expressed more commonly in recurrent disease than in primary tumors, in more aggressive subtypes, and in more advanced disease stages. There was a trend toward better survival and progression-free survival in patients who were negative for IGF-1R or p-AKT expression in the whole series. When only the 91 primary tumors, IGF1R expression was associated with worse progression-free survival (P