TKT and neoplasm: For example, the phase I/II TREAT-ME1 clinical trial evaluated the safety and efficacy of autologous MSCs delivering the gene HSV-TK (MSC_apceth_101) in combination with GCV, showing acceptable safety, tolerability and some signs of effectiveness in reducing tumour growth and metastases in advanced gastrointestinal adenocarcinoma (NCT02008539) [233].