Ma et al developed two high-affinity and high-specificity human CDH17 nanobodies (A1 and E8), which showed significant anti-tumor effects in gastric cancer PDX (including mouse PDX and zebrafish PDX) when fused with imaging probes and toxins PE38,153 offering a promising new imaging modality and clinical translational therapy for gastric cancer treatment. Here, CDH17 is linked to gastric cancer.