GPA33 and neoplasm: The surface persistence of the GPA33 antigen and normal intestinal epithelium shedding contribute to the very good retention in tumor tissue and the rapidly released form normal cells (Almqvist et al. 2006; Ackerman et al. 2008), supporting the selective localization into the tumor of mAbA33 immunoconjugates, as shown by in vivo biodistribution in mice models (Scott et al. 2005; Almqvist et al. 2006; Panjideh et al. 2008).