Osteopontin as a Serum Biomarker in Uveal Melanoma: A Pilot Study

Abstract

Abstract: : Purpose: Serum osteopontin levels correlate with aggressive behavior and metastasis in breast, ovarian and pancreatic cancers. This study was designed to explore the putative diagnostic role of serum osteopontin as a biomarker in the identification of patients with metastatic uveal melanoma. Methods: Serum osteopontin levels of patients who had been treated for primary uveal melanoma and who were disease–free for at least 10 years (n=16) and patients who had metastatic melanoma to the liver (n=12) were measured by an ELISA assay (Assay Designs, Ann Arbor, MI). In five of these patients, paired serum samples six months before and immediately after the appearance of metastasis were available for analysis. Results: The mean serum osteopontin level was 9.44 ng/ml (range: 3.7 – 30) in patients who were disease–free for at least 10 years versus the mean level of 27.97 ng/ml (range: 5.1 to 139) in patients with metastatic melanoma (p = 0.0074 by Kruskall–Wallis test). In the five patients who were disease–free after treatment of the primary and who subsequently developed liver metastases, the serum osteopontin level rose two– to nine–fold. Conclusions: In this pilot study, we detected significant differences in serum osteopontin levels between uveal melanoma patients who were disease–free for at least 10 years and patients with metastatic uveal melanoma to the liver. Serum osteopontin may be a useful non–invasive marker in patients with uveal melanoma, pending validation of sensitivity and specificity.

Keywords: melanoma • oncology • tumors