Pilot Screening Study of the Angiogenesis Factor Pleiotrophin (PTN) in Serum Samples from Patients of Various Disease Groups

Introduction: The secreted growth factor pleiotrophin (PTN) belongs to the midkine family of heparin-binding growth factors and is tightly regulated during embryogenesis. In contrast to its very limited expression in normal adult tissues, PTN protein levels are markedly increased in different tumors, with PTN showing mitogenic, chemotactic, transforming, pro-angiogenic, pro-invasive and pro-metastatic activity. However, little is known about PTN upregulation in diseases other than cancer. The aim of this study was to investigate PTN serum levels in patients with various non-malignant chronic or acute disorders, and in pregant women, compared to healthy nonpregnant blood donors as negative control group.Materials and Methods: PTN serum levels were determined by a sandwich ELISA.Results: PTN serum levels were found to be significantly elevated with a p-value of <0.05 in patients with the acute non-malignant disorders, acute inflammation, acute vascular disease and acute trauma. In patients with chronic leukemia and solid tumors, and pregnancy, increased PTN serum levels were detected as well.Conclusion: Beyond its described functions in solid tumors and in the central nervous system, these data indicate that PTN is an acute phase protein in the adult organism and that, due to its upregulation under various non-cancer conditions, special caution must be taken when exploring PTN serum levels as potential tumor marker.