Plasma transforming growth factor-β1 level before radiotherapy correlates with long term outcome of patients with lung carcinoma

Abstract

BACKGROUND. Plasma transforming growth factor-β1 (TGFβ1) levels are increased in many malignancies at the time of diagnosis, including all forms of lung carcinoma. Therefore, the potential use of TGFβ1 as a plasma marker to predict the long term outcome of lung carcinoma patients treated with radiotherapy (RT) was evaluated. METHODS. Plasma samples for 59 newly diagnosed lung carcinoma patients were assayed for TGFβ1 before RT (pre RT), at the end of RT (end RT), and during follow-up after RT. TGFβ1 was extracted from plasma using an acid-ethanol method. An enzyme-linked immunoadsorbent assay was used to quantify the plasma TGFβ1 levels. The normal value for this assay is ≤7.5 ng/mL. Disease status at last follow-up was without knowledge of TGFβ1 levels. Comparisons within groups and between groups were estimated using analysis of variance and the Student t test for unpaired data, respectively. RESULTS. The 59 patients were divided into 2 groups according to their disease status at last follow-up: those with no evidence of disease (NED) (n = 13) and those with disease (WD) (n = 46). The median follow up was 26.8 months and 12.4 months, respectively, for the NED and WD groups. No significant differences were found in the clinical characteristics between the two groups. The plasma TGFβ1 level before RT was significantly higher in the WD group (mean ± standard error of the mean [SEM]= 12.5 ± 1.7 ng/mL; median = 8.6 ng/mL) compared with the NED group (mean ± SEM = 6.0 ± 1.0 ng/mL; median = 6.0 ng/mL) (P = 0.037). At the time of last follow-up, WD patients had a significantly higher plasma TGFβ1 level (mean ± SEM = 11.6 ± 1.3 ng/mL; median = 9.6 ng/mL) compared with NED patients (mean ± SEM = 3.7 ± 0.5 ng/mL; median = 3.6 ng/mL) (P = 0.002). CONCLUSIONS. These data demonstrate that plasma TGFβ1 may be a useful tumor marker in patients with lung carcinoma.