TROP-2, also called tumor associated calcium signal transducer 2 (TACSTD2), gp50 and T16, is a type I cell surface glycoprotein that is highly expressed on human carcinomas. (Trop-2) is necessary for tumorigenesis and invasiveness of colon cancer cells, as both are inhibited when Trop-2 expression is suppressed by RNA interference. Defects in trop-2 are the cause of gelatinous drop-like corneal dystrophy (GDLD) also known as lattice corneal dystrophy type III. GDLD is an autosomal recessive disorder characterized by grayish corneal amyloid deposits that cause severe visual impairment.