Predictive significance of bone sialoprotein and osteopontin for bone metastases in respectable non-small cell lung cancer: A retrospective study

Abstract

7666 Background: Bone sialoprotein (BSP) and osteopontin (OPN) have been demonstrated predictive of bone metastases in breast and prostate carcinoma, consistent with the proposed role of BSP as a stimulator of bone mineralization and OPN in differentiation and activation of osteoclasts. Bone metastasis (BM) is often developed in non-small-cell lung cancer (NSCLC), but no predictive biomarker was identified for high risk of metastatic bone dissemination. Methods: 180 completely resected NSCLC patients were included in this study. 38 patients subsequently developed BM. Paraffin embedded primary tumor tissue of patients were supplied to produce a tissue microarray, and immunohistochemistry method was used for evaluation the expression of BSP and OPN. Different expressions of these two biomarkers among BM group and non-BM group were estimated by χ2 test. Bone metastasis-free survival was analyzed by Kaplan-Meier method. The prognostic impact of clinicopathologic parameters and biomarker expression was evaluated by Cox propotional hazards model. Results: BSP expression was associated with BM (P=0.027), while OPN expression could not reach statistical significance (P=0.495). Univariate analysis demonstrated that expression of BSP (P=0.036), N stage (P=0.000) and clinical stage (P=0.001) were associated with time interval to BM. Multivariate analyses showed BSP expression (RR=1.779, P=0.012) and clinical stage (RR=1.620, P=0.005) were independent prognostic factors for BM. Conclusions: BSP protein expression in the primary resected NSCLC is strongly associated with BM and could be used to identify high-risk patients. Correlation of OPN protein expression and bone metastasis need further investigation. No significant financial relationships to disclose.