GUCY2C and neoplasm: For the GSU experiments, mice from each experimental group received focal irradiation on day 8 post-implantation, followed by the infusion of a single intravenous dose of 2 x 106 CAR-T cells recognizing guanyl cyclase-C (GCC) expressed on the GSU tumor cells 24 h after receiving their last dose of radiotherapy (Figure 1A).