Background: Midkine (MK), a heparin-binding growth factor, has an important role in cancer progression in different tumor types. The aim of this study was to determine MK expression in gastrointestinal stromal tumors (GISTs) that derive from the institial neuronal cells of Cajal in myenteric plexus of the intestine.
Materials and Methods: 57 patients with GIST that were surgically treated between 1985 and 2004 were chosen retrospectively and a clinical follow-up was performed.
Results: MK was detected in 31 (55%) of 57 surgically resected GISTs by immunohistochemistry. A significant worse outcome of MK-positive patients was found (p<0.05; log rank test). Multivariate Cox regression analysis showed an independent prognostic impact (relative risk for overall survival 3.64; p<0.05). Interestingly, MK expression was significantly associated with mitotic rate (p<0.05; Chi-squared test), but not with tumor size (p=0.97).
Conclusion: Taken together, MK is an independent prognostic marker for surgically treated GIST patients. Since it can be detected in peripheral blood, future studies might focus on the usefulness of MK as a peripheral tumor marker in GIST patients.