A CROSS-LINKING ASSAY ALLOWS THE DETECTION OF RECEPTORS FOR THE SOMATOSTATIN ANALOG, LANREOTIDE IN HUMAN BREAST-TUMORS

Hypothalamic somatostatin and its synthetic analogues inhibit the cell growth of several tumour models. The somatostatin analogue lanreotide (somatuline or BIM23014C) inhibits both the in vivo and in vitro cell growth of various mammary tumours. In order to evaluate the presence of receptors for lanreotide in breast tissue, samples from 41 female a nd 2 male patients were analysed by a cross-linking assay. All the sam ples examined possessed at least one subtype of lanreotide binding pol ypeptide, however, different polypeptide patterns were observed. The t wo major complexes had molecular weights of 57 kD and 42 kD. The previ ously demonstrated antiproliferative activity of lanreotide and the hi gh percentage of positive tumours supports the use of lanreotide in cl inical trials. However, the role of each receptor subtype in the contr ol of breast cell proliferation requires further characterisation.