A cross-linking assay allows the detection of receptors for the somatostatin analogue, lanreotide in human breast tumours.

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 and 2 male patients were analysed by a cross-linking assay. All the samples examined possessed at least one subtype of lanreotide binding polypeptide, however, different polypeptide patterns were observed. The two major complexes had molecular weights of 57 kD and 42 kD. The previously demonstrated antiproliferative activity of lanreotide and the high percentage of positive tumours supports the use of lanreotide in clinical trials. However, the role of each receptor subtype in the control of breast cell proliferation requires further characterisation.