By binding to different integrins, OPN can exert multiple physiological functions, including (a) promoting the invasiveness of tumor cells and supporting tumor growth and metastasis; (b) facilitating fibroblast migration and the progression of tissue fibrosis; (c) enhancing immune cell infiltration and regulating the survival, proliferation, migration, and differentiation of immune cells; and (d) participating in tissue repair and inflammatory responses (98–102). Here, SPP1 is linked to neoplasm.