SPP1 and neoplasm: The mean serum level of B7-H4 was significantly higher in patients with advanced tumor stage compared in those with early tumor stage (P = 0.017), and Mann–Whitney U analysis also showed that B7-H4, OPN, and TPS serum expressions were significantly related to distant metastasis (P = 0.0041, P = 0.015, and P = 0.021, respectively).