Osteopontin Affects Oncological Outcome after Liver Resection for Colorectal Metastasis

Abstract

Introduction: Osteopontin (OPN) - a chemoattractant and matrix protein - was previously described to be expressed by a variety of malignant tumors. As such, colorectal carcinoma was found to produce OPN. Further, a close relation of OPN to oncological outcome could be identified. Yet, OPN was not investigated in patients with colorectal cancer liver metastasis (CRCLM). Method: Within this analysis 48 patients undergoing liver resection for CRCLM were included. Circulating OPN was evaluated prior to the operation. Further, OPN was stained on tumor tissue gathered during liver resection. Patients were followed up for disease recurrence. Results: OPN expression in tumor tissue was tightly associated to circulating levels. Further, OPN was found to be significantly increased in patients that develop disease recurrence within two years after curative liver resection (median OPN no recurrence = 49.97 ng/mL vs median OPN recurrence = 72.38 ng/mL, p = 0.013). This difference was found to obtain a strikingly high predictive potential evaluated via receiver operating characteristics (AUC = 0.833, p = 0.015). Based on this analysis an optimal cut-off was identified at 60 ng/mL of OPN. Indeed, patients above this cut-off showed a significantly reduced disease-free survival when compared in a Kaplan-Meier analysis (difference in median disease-free survival = 1.3 years, p = 0.042). Conclusions: OPN is a marker for early disease recurrence in patients suffering from CRCLM. Thus, assessment of OPN might be a useful tool for preoperative patient evaluation and should hence be included in the work-up of this patient cohort.