Pigment epithelium-derived factor (PEDF) is a multifunctional protein that plays a crucial role in various biological processes, including the regulation of angiogenesis, inflammation, and neuroprotection. It is primarily secreted by the retinal pigment epithelium (RPE) and has been shown to have anti-angiogenic, anti-inflammatory, and neuroprotective properties. Research on PEDF has focused on its potential therapeutic applications in a variety of diseases, including cancer, diabetic retinopathy, and neurodegenerative disorders. Studies have shown that PEDF can inhibit tumor growth, reduce inflammation in the eye, and protect neurons from degeneration. Overall, research on pigment epithelium-derived factor continues to uncover its diverse roles in various physiological processes and its potential as a therapeutic target for multiple diseases.