IGF-IR: A new prognostic biomarker for human glioblastoma

Glioblastomas (GBMs) are the most common malignant primary brain tumors in adults. These tumors are refractory to conventional treatment approaches including surgical resection, radiotherapy and chemotherapy. The insulin-like growth factor (IGF) system is a complex network that includes soluble ligands (IGFI and IGFII), cell surface transmembrane receptors (IGF-IR and IGF-IIR), and soluble high-affinity binding proteins (IGFBP-1 to IGFBP-6). Many studies have reported a role for the IGF system in the regulation of tumor cell biology. However, the role of the different actors of this system remains unclear in GBM. The present study aimed to investigate the potential prognostic value of both the IGF ligands (IGFI and IGFII) and receptors (IGF-IR and IGF-IIR) in a large cohort of human GBMs. Tissue microarray and image analysis were conducted to quantitatively analyze the immunohistochemical expression of these proteins in 218 human GBMs. Both IGF-IR and IGF-IIR were overexpressed in GBMs compared to normal brain (p