Toda et al. found that Trop-2 expression was significantly higher in anaplastic thyroid carcinoma (ATC) undifferentiated from papillary thyroid carcinoma (PTC) compared to ATC undifferentiated from follicular thyroid carcinoma (FTC) and de novo ATC. The gene discussed is TACSTD2; the disease is thyroid gland undifferentiated (anaplastic) carcinoma.