Gene expression of insulin-like growth factors and receptors in neoplasticprostate tissues: Correlation with clinico-pathological parameters

The insulin-like growth factor (IGF) system has been shown to regulate pros tate cancer cell growth in vitro and, possibly in vivo. in this study we ex amined RNA expression of IGF ligands and their receptors in 23 paired benig n and neoplastic prostate tissues. In addition to comparing gene expression of IGF ligands and receptors between benign and neoplastic tissue samples, we correlated IGF-I, IGF-II, IGFR-1, and IGFR-2 RNA levels in tumor sample s with prognostic clinico-pathological parameters such as stage, grade, Gle ason score, perineural or extraprostatic invasion. We found higher IGF-I RN A levels in benign vs. malignant tissues (p = 0.014), whereas IGF-II RNA ex pression was higher in tumors with high Gleason score (GS) (p = 0.045). Usi ng the Spearman rank correlation test we also found a positive correlation between IGFR-2 RNA levels and GS (p = 0.01). No correlation was found betwe en expression of IGF ligands and receptors and tumor grade, stage perineura l invasion, or extraprostatic involvement. We conclude that differential ex pression of certain IGF system components may be important in the biology a nd clinical behavior of prostate cancer.