TACSTD2 and digestive system carcinoma: TROP-2 over-expression was found in various human epithelial cancers, such as breast, lung, oral, urothelial, prostate, pancreatic, cervical, ovarian, and gastrointestinal carcinomas, and is linked to an overall poor prognosis, leading to the development of TROP-2 targeted ADC treatment for malignant solid tumors (Ambrogi et al. 2014; Liu et al. 2013; Fang et al. 2009; Nakashima et al. 2004; Jiang et al. 2013; Mühlmann et al. 2009).