The pooled data of studies showed that high OPN expression was significantly associated with high tumor grades (OR = 2.24, 95% CI 1.55–3.23), lymph node metastasis (OR = 2.36, 95% CI 1.71–3.26) and tumor distant metastasis (OR = 2.38, 95% CI 1.01–5.60). This evidence concerns the gene SPP1 and neoplasm.