As regards the association between OPN expression and clinicopathological parameters, such as age, sex, histological type, primary tumour size, histological grading, relapses during follow-up and status (alive vs dead), we observed statistically significant correlations between OPN expression and grading (P=0.00004), sex (P=0.006) and relapse (P=0.02). This evidence concerns the gene SPP1 and neoplasm.