hAG-2 and hAG-3 each have a predicted N-terminal cleavable secretory signal sequence (http://psort.nibb.ac.jp) and we previously demonstrated that hAG-3 was localised to endosomes in the T47D breast cancer cell line, further evidence that it is a secreted protein (Adam et al, in Press). Here, AGR3 is linked to breast carcinoma.