Abstract
Pleiotrophin is a heparin-binding growth factor involved in the differentiation and proliferation of neuronal tissue during embryogenesis, and also secreted by melanoma and breast carcinoma cells. Pleiotrophin exhibits mitogenic and angiogenic properties and has been shown to influence the vascular supply, expansion and metastasis of tumour cells. Our aim was to study the serum and plasma concentrations of pleiotrophin and the classical angiogenic growth factor vascular endothelial growth factor. Using a specific ELISA-test we studied patients with small cell lung cancer (n=63), and patients with non-small cell lung cancer (n=22) in comparison to healthy control subjects (n=41). In most of the lung cancer patients (81%), we found serum levels of pleiotrophin above those of control subjects (P<0.001). Of the 63 small cell lung cancer patients in the study pleiotrophin serum levels were elevated in 55 cases (87%) and in 14 cases (63%) of the 22 non-small cell lung cancer patients. Pleiotrophin mean serum concentrations were 10.8-fold higher in the tumour patient group as compared to the control group (P<0.001). Furthermore, pleiotrophin serum levels correlated positively with the stage of disease and inversely with the response to therapy. Plasma vascular endothelial growth factor concentrations were elevated in only in 28.6% of small cell lung cancer and 45.5% of non-small cell lung cancer patients by an average of 2.3-fold. Quite strikingly, there was no apparent correlation between the plasma vascular endothelial growth factor concentration and the stage of disease. Our study suggests that pleiotrophin may be an early indicator of lung cancer and might be of use in monitoring the efficacy of therapy, which needs to be confirmed by larger studies.