This study further revealed that DNA damage was quite homogeneous in CEA-positive A431 tumours in mice administered 125I-anti-CEA mAbs, despite radioactivity being localised mainly at the periphery of the tumour, suggesting a local bystander effect on non-targeted cells that could be mediated by damage to the cell membrane of targeted tumour cells (Paillas et al. 2016). This evidence concerns the gene CEACAM5 and neoplasm.