RAPID COMMUNICATION: Human Ovarian Cancers Express Somatostatin Receptors

ABSTRACT. Characteristics of receptors for somatostatin (SST) analog RC-160 on 17 surgical specimens of human epithelial ovarian cancer and two human ovarian cancer lins were determined by ligand competition assays. The expression of mRNA for four SST receptor subrypes (sst1, sst3, sst2A, sst5) was investigated by RT-PCR. Thirteen of 17 specimens (76%) exhibited high affinity binding sites for RC-160 with Kd = 6.55 nmol/L and a Bmax = 575.4 fmol/mg membrane protein. Specific receptors for RC-160 were also found in xenografts of OV-1063 and UCI-107 human ovarian cancer lines. The mRNA for sst1 was detected in 65% of the ovarian cancer specimens, while the incidence ov sst2A, sst3, and sst5 was 65%, 41% and 24%, respectively. Both ovarian cancer cell lines also expressed mRNA for these four subtypes. The presence of these SST receptor subtypes in human ovarian cancers allows the use of SST analogs and their radionuclide and cytoxic derivatives for the diagnosis and treatment of this malignancy.