Background: Ewing sarcoma family of tumors (ESFTs) are the second most common bone tumor, that most often affects persons ages 3-40 years. The ESFTs rely on signaling through the insulin-like growth factor-1 receptor (IGF-1R) for growth and transformation. The current studies were performed to determine the levels of IGF-1 and IGF binding protein-3 (IGFBP-3) in patients with ESFT. The authors then performed an exploratory analysis to evaluate whether IGF parameters could differentiate event free or overall survival in ESFT patients.
Methods: The authors measured serum levels of IGF-1 and IGFBP-3 by using a radioimmunoassay from 111 patients with ESFT with a median follow-up of 13 years from diagnosis.
Results: The IGF-1 levels were lower among patients with metastatic disease to the bones or the bone marrow compared with patients without metastasis to these sites (p2 = 0.021 and 0.0038, respectively). IGFBP-3 is known to sequester IGF-1; the ratios of IGFBP-3 to IGF-1 were evaluated. Patients with metastatic disease to any site had higher IGFBP-3 to IGF-1 ratios than patients with localized disease (p2 = 0.0067). There was a trend toward increased survival in patients with localized disease who had high IGFBP-3 to IGF-1 levels. Metastatic patients showed a similar trend.
Conclusions: Levels of IGF-1 and IGFBP-3 in ESFT patients can identify patients with the most widespread disease. The IGFBP-3 to IGF-1 ratio in patients with either localized or metastatic disease identified patients with a trend toward increased survival. Further prospective evaluation with higher patient numbers might show a prognostic role for the IGFBP-3 to IGF-1 ratio in patients with ESFT.
Copyright 2001 American Cancer Society.