LAMP1 and nasopharyngeal carcinoma: The GST-PFO-positive vesicles, found only in NPC cells, also stained with filipin, antibodies against lysosomal-associated membrane protein 1 (LAMP-1) and lysobisphosphatidic acid (LBPA), indicating that the procedure detected accumulation of cholesterol in late endosomes/lysosomes in NPC cells.