However, there was no significant correlation between OPN level and tumor size in our study, as tumors < 3 cm, present in 40% of patients, showed median plasma OPN level 140 with a range of (100 - 336 ng/mL), and tumors ≥ 3 cm, present in 60% of patients, showed median plasma OPN level 229 with a range of (131 - 438 ng/mL) (P value: 0.28). This evidence concerns the gene SPP1 and neoplasm.