PLG and viral infectious disease: To clarify the mechanism of SPARC in ovarian cancer invasion and metastasis, after viral infection, we detected the expression of cellular adhesion molecule E-cadherin and integrins, which mediated cell-cell adhesion and cell-extracellular matrix adhesion, and the expression and activity of proteolytic enzymes such as plasminogen activator/plasmin system (uPA-uPAR) and matrix metalloproteinases (MMPs), which degraded the extracellular matrix (ECM).