TACSTD2 and ovarian cancer: TACSTD2 (tumour-associated calcium signal transducer 2), also known as Trop2 (trophoblast antigen 2) or GA7331 (gastrointestinal tumour-associated antigen), is a cell surface glycoprotein that has been implicated in cancer metastasis and as a poor prognosis marker 10-13, including ovarian cancer.