Abstract B44: Survivin protein detection is a promising biomarker in the serum of gastroenteropancreatic neuroendocrine tumor (GEP‐NET) patients

Background: The bifunctional protein survivin is a powerful prognostic marker in GEP‐NET disease as measured by immunohistochemical methods in tumor tissues. The present study was focused to investigate if survivin can also be detected in the serum of GEP‐NET patients and to evaluate its potential diagnostic role. Aim: To establish a method by which the serum levels of survivin can be used as a predictive value in the treatment outcome of patients with GEP‐NET disease. Materials and Methods: In 2007, serum samples were obtained from patients with well‐differentiated GEP‐NET disease (n=22) either at Charite‐Campus Benjamin Franklin (n=8) or at the University Hospital of Hamburg‐Eppendorf (n=14), hematological malignancies (HM) and solid cancers (n=22), as well as healthy volunteers (n=25), the last all obtained at the Charite. All patients had given their informed consent to this pilot study. The patients of the GEP‐NET group had either stable disease with metastasis, predominantly to the liver (n=14), or were progressive at the time of venipuncture (n=6). 9 foregut tumors, 10 midgut tumors and 3 hindgut tumors were included, a third of those functionally active. Most of the patients received any kind of bio‐ or chemotherapy. The mean age of GEP‐NET patients was 61.1 years (range 29–81), whereas the mean age of patients with HM and solid tumors was 55.9 years (range 30–82). Enzyme‐linked immunosorbent assay (ELISA) analysis was used for determination of survivin protein serum levels. Results: There was a statistically significant increase of the survivin protein serum levels in patients with HM and solid cancers compared to the healthy controls (p=0.009). The difference in survivin serum levels between healthy controls and patients with GEP‐NETs did not reach statistical significance (p=0.089). No correlation to clinical features like localization of the tumor, functional activity, Chromogranin A levels or kind of therapy was found. However, survivin serum levels tended to be higher in patients with a greater tumor burden. Conclusion: This is the first study to quantify survivin protein levels in the serum of GEP‐NET patients. The results of this small pilot study should be evaluated in further clinical trials by correlating survivin serum levels before and after therapy in order to define its potential diagnostic and prognostic use. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B44.