Liang [48] transfected lentivirus into tumor cells to upregulate/downregulate OPN expression and found that the nuclear expression of OPN increased cadherin expression, induced MET of tumor cells, and remodeled the epithelial phenotype of tumor cells, which suggested that the dynamic transformation process of the epithelial phenotype-mesenchymal phenotype-epithelial phenotype in tumor cells was inseparable from the role of OPN. The gene discussed is SPP1; the disease is neoplasm.