Clinicopathological and prognostic significance of osteopontin expression in patients with prostate cancer: a systematic review and meta-analysis

Background: Evaluation of the feasibility for osteopontin (OPN) to serve as a biomarker in the prognosis and clinical-pathological features of prostate cancer patients. Methods: The original publications related to osteopontin and prostate cancer were comprehensively searched in the online databases, including PubMed, Embase, Cochrane Library, Web of Science, Medline, Wanfang and China National Knowledge Infrastructure up to August 2019. Results were analyzed by Revman 5.3 and Stata 12.0. Results: A total of 21 studies were included in the analysis and the result showed that the positive OPN expression group had a lower overall survival than the negative expression group (univariate: HR=2.32, 95%CI [1.74, 3.10], multivariate: HR=2.41, 95%CI [1.63, 3.57]) and a lower biochemical relapse-free survival than the negative group (univariate: HR=1.42, 95%CI [0.92, 2.17], multivariate: HR=1.61, 95%CI [1.39, 1.87]). In addition, there was a higher expression level of OPN in prostate cancer tissues than in normal prostate tissues (OR=46.55, 95%CI [12.85, 168.59], P<0.00001) and benign prostatic hyperplasia tissues (OR=11.07, 95%CI [3.43, 35.75], P<0.0001). Moreover, OPN positive expression was also related to high Gleason score (OR=2.64, 95%CI [1.49, 4.70], P=0.0009), high TNM stage (OR=3.15, 95%CI [1.60, 6.20, P=0.0009), high Whitmore-Jewett stage (OR=2.53, 95%CI [1.06, 6.03], P=0.04), high lymph node (OR=3.69, 95%CI [1.88, 7.23], P=0.0001), and distant metastasis (OR=8.10, 95%CI [2.94, 22.35], P=0.01). There was no difference observed in the differentiation of prostate cancer (OR=1.79, 95%CI [0.39, 8.33], P=0.46). Conclusion: Osteopontin could be recognized as a promising diagnostic and prognostic biomarker for prostate cancer patients.