Prognostic value of plasma transforming growth factor-beta in patients with glioblastoma multiforme

We investigated whether the postoperative concentration of circulating transforming growth factor beta (TGF-beta) yields prognostic value in patients with glioblastoma multiforme (gbm). Blood was collected from 20 healthy volunteers and in 28 patients with mainly glioblastoma multiforme (gbm), both before radiotherapy, during and after 4 weeks of irradiation. Both latent and active TGF-beta were quantified directly in the blood plasma using a bioassay with mink lung epithelial cells transfected with a plasminogen activator inhibitor-1 promotor luciferase construct. The average plasma concentration of TGF-beta before radiotherapy for gbm patients was 26.2 ng/ml, which was significant higher than in normal controls (16.2 ng/ml, p=0.02). No correlation was found between TGF-beta and survival, nor between plasma TGF-beta and the diameter of the postoperative contrast-enhancing lesion. The pattern of plasma TGF-beta during radiotherapy did not correlate with the clinical course of patients, nor with the fractionation scheme. Plasma TGF-beta did not reveal a clinical useful prognostic value for gbm patients, which is partly due to the large variation in TGF-beta plasma levels between individual patients.