TROP-2, also known as tumor-associated calcium signal transducer 2, is a 35 kDa, 323-amino-acid, type-1 transmembranous glycoprotein, and its overexpression is present in the majority of human carcinomas, including thyroid carcinoma, and can serve as a potential diagnostic marker for PTC [17,38]. The gene discussed is TACSTD2; the disease is carcinoma.