Among these proteins, pigment epithelium-derived factor serves a potential role in the treatment of RB, and stimulated by retinoic acid 6 may serve as a potential protein involved in RB development.
Pigment epithelium-derived factor (PEDF), a glycoprotein that belongs to the superfamily of serine protease inhibitors, was first purified from the conditioned media of human retinal pigment epithelial cells as a factor with potent neuronal differentiating activity in human retinoblastoma cells.
Preliminary studies with cultured human Y79 retinoblastoma cells indicate that expression of PEDF is associated with relatively undifferentiated, proliferating cells rather than their differentiated, slow-growing counterparts.