Correlation between both serum osteopontin/osteonectin and bone remodelling parameters, inflammatory/metabolic variables and survival in metastatic cancer patients with tumors at different sites

Osteopontin (OPN) is a secreted, integrin-binding phosphoprotein that has been correlated with tumor grade and stage and disease progression in several tumor types.The secreted protein, acidic and rich in cystein (SPARC) is closely related to progression, invasion, angiogenesis and metastatic process of several malignant tumors. The aim of the study was to verify in a population of advanced cancer patients with tumors at different sites whether there is a correlation between circulating levels of OPN and SPARCand clinical parameters (such as bone metastases, pain and quality of life), circulating bone remodeling (skeletal) parameters (alkaline phosphatase, C- and N-terminal fragments of type I collagen, osteocalcin, Vitamin D), inflammatory (IL-8 and TNF-alpha) and metabolic parameters (BMI, serum cholesterol and triglycerides). Materials and Methods: From April 2010 to August 2010, we enrolled 33 metastatic cancer patients with tumors at different sites (M/F: 16/17, mean age 66 years): 17 patients with bone metastases, 16 with metastases not involving bone. Comparison between groups (controls vs cancer patients and cancer patients with vs without bone metastases) was performed by two-sided Student’s t test. Correlation between OPN/SPARC and the other variables was performed by Spearman’s correlation analysis. Results: OPN and SPARC in cancer patients were significantly higher compared to controls but did not differ between patients with or without bone metastases. OPN showed a positive significant correlation with C and N terminal fragments of type I collagen (r = 0.390 and r = 0.410, p = 0.024 for both), IL-8 (r = 0.390, p = 0.034) and a negative significant correlation with quality of life (r = −0.400, p = 0.025) and BMI (r = −0.300, p = 0.046). SPARC showed a positive significant correlation with BMI (r = 0,360, p = 0.049). Moreover, patients with 3 month survival (613.7±229.2 ng/ml versus 195.8±165 ng/ml, p < 0.001). Conclusion: The results of the present study show that high OPN levels are associated with poor survival in advanced cancer patients. Further studies are warranted to assess the role of OPN and SPARC to both monitor the effects of antineoplastic regimens and to assess them as potential targets of new treatment strategies