SPP1 and neoplasm: Significantly higher plasma OPN level was detected in patients with tumor size over 5 cm (180.4 vs 140.7 ng/ml, p = 0.003; 1C), higher stage (187.9 vs 137.0 ng/ml, p<0.001; Fig 1D) and metastatic CRC (197.0 vs 148.7 ng/ml, p = 0.003; Fig 1E).