For example, TCBs targeting the epithelial cell-adhesion molecule (EpCAM) and carcino-embryonic antigen (CEA), were developed to treat solid tumours, but were found to trigger diarrhoea in phase I clinical trials, suggesting on-target off-tumour intestinal reactivity, consistent with EpCAM and CEA expression in the healthy intestine23,24. Here, CEACAM5 is linked to neoplasm.