SPP1 and neoplasm: Using a univariate Cox regression hazard model for STS patients with high OPN protein level in the serum or in tumor tissue extracts, the risk of tumor-related death was a 2.2 (95% confidence interval (CI) 1.01-5.1; p < 0.05) and 3.7 (95% confidence interval (CI) 1.3-10.4; p = 0.01), respectively (Fig. 2, Table 3).