Co-expressed peptide receptors in breast cancer as a molecular basis for in vivo multireceptor tumour targeting.

Breast cancers can express different types of peptide receptors such as somatostatin, vasoactive intestinal peptide (VIP), gastrin-releasing peptide (GRP) and NPY(Y(1)) receptors. The aim of this in vitro study was to evaluate which is the most appropriate peptide receptor or peptide receptor combination for in vivo diagnostic and therapeutic targeting of breast cancers. Seventy-seven primary breast cancers and 15 breast cancer lymph node metastases were investigated in vitro for their expression of somatostatin, VPAC(1), GRP and NPY(Y(1)) receptors using in vitro receptor autoradiography on successive tissue sections with (125)I-[Tyr(3)]-octreotide, (125)I-VIP, (125)I-[Tyr(4)]-bombesin and (125)I-[Leu(31),Pro(34)]-PYY respectively.