IGF-1 and IGFBP-3 in testicular germ ceil tumors.

Testicular cancer is a disease with elusive pathogenesis. Recent studies demonstrated a relationship between insulin- like growth factor (IGF) signaling pathway and the pathogenesis of various types of cancer. On the other hand inconclusive data correlate increasing height, a trait depending on IGF signaling pathway, with increasing incidence of testicular cancer. Thus, it is possible that IGF system may be implicated in the pathogenesis of germ cell tumors. The purpose of the study was to identify the role of IGF signaling pathway in the pathogenesis of testicular germ cell tumors (GCTs). 50 patients with GCTs prior to the onset of chemotherapy and 16 male age matched controls were enrolled. Three blood samples were drawn from the patients, the first at baseline, the second 20-30 days after completion of the second cycle of chemotherapy and the third 9-14 months after the completion of chemotherapy; and one blood sample was drawn from the controls. We measured serum IGF-1 and IGFBP-3 and calculated their molar ratio using quantitative sandwich enzyme immunoassay technique. Patients and controls had similar demographic characteristics. Mean IGF-1/IGFBP-3 molar ratio was higher in patients than controls (0.27±0.07 vs. 0.11±0.03; p=0.02'7). IGF-1 decreased significantly between the baseline and 1 year after chemotherapy was completed (261.2±483 vs. 96.4±23.1 ng/mL, respectively; p<0.001) and between the second sample and the third sample (205.7±41.7 vs. 96.4±23.1 ng/mL; p<0.001 IGFBP-3 was increased after chemotherapy (mean values of first and second samples were 3545±687.3 vs. 4714±827.1 ng/mL; p=0.045, and mean values between first and third samples were 3591±697.6 vs. 5145±1073.2 ng/mL; p=0.005 IGF1/IGFBP3 molar ratio was found to decrease after initiation and completion of chemotherapy (mean values were: 0.269±0.05 vs. 0.211±0.04; between the first and third samples, p=0.035; 0.308±0.07 vs. 0.083±0.02 between the second and third samples, p<0.001and 0.211±0.04 vs. 0.084±0.02 between the first and second samples, p<0.00). The concept that IGF signaling system has a role in germ cell cancer pathogenesis is an appealing idea and our study seems to provide further evidence in favor of our initial hypothesis, although larger prospective studies are needed to further elucidate it. [ABSTRACT FROM AUTHOR]