CEACAM5 and cancer: In contrast to RIT using antibodies against tumour cell-associated antigens which are expressed only in certain cancers, such as carcinoembryonic antigen in colorectal tumours (Pedley et al, 2001; Mayer et al, 2003), RIT with L19-SIP antibody, which selectively targets tumour vessels, has the advantage of being effective in a wide range of solid tumours (Berndorff et al, 2005; Spaeth et al, 2006; Tijink et al, 2006).