Pigment epithelium-derived factor (PEDF) is a potent and versatile endogenous inhibitor of angiogenesis.13 Previous studies demonstrated that PEDF is a favorable prognostic indicator in colorectal, pancreatic, lung and breast cancer.14, 15, 16, 17 There is a complex mechanism underlying the antitumor effects of PEDF, which includes inhibition of angiogenesis and tumor cell migration, induction of apoptosis and pro-tumor differentiation in certain tumor cell types.18 However, it is still unclear the exact role of endogenous PEDF in EMT occurrence and NPC metastasis. The gene discussed is SERPINF1; the disease is breast carcinoma.