TACSTD2 and digestive system neoplasm: Trop2 is highly expressed on the cell surface of gastrointestinal tumors such as CRC or GC.530,531 Studies using Trop2/PD-L1 CAR-T cells in mouse models of gastric cancer showed reduced tumor growth upon intratumoral injection of the engineered T-cell.532 Also, as these CAR-T cells target both Trop2 and PD-L1, they produced higher levels of IFN-y and IL-2, thereby increasing the immune response.532 Another target for CAR-T cell therapy is HER2, as it is overexpressed in 30% of solid tumors.