Abstract

Kinins are vasoactive peptides released from large precursors by the serine protease hK1 kallikrein. Once formed, they bind two types of G protein-coupled receptors called B1 and B2. Recent reports indicate that the kinin B2 receptor agonist, bradykinin induces the proliferation of both normal and neoplastic breast cells in culture. Our aim was to determine the expression of kinin B2 and also B1 receptors in breast tumours and in the MCF-7 cell line, derived from metastatic breast carcinoma. Expression of kinin receptors was assessed by autoradiography, immunohistochemistry and RT-PCR. Autoradiography was carried out on frozen sections and tissue binding sites were determined using iodinated kinin B1 (Tyr-Gly-Lys-Aca-Lys-des [Arg9]-bradykinin) and B2 (Tyr0-bradykinin) receptor ligands. Seven benign lesions (5 fibroadenomas, 1 cystic hyperplasia, and 1 phyllodes tumour) and 21 malignant neoplasms