Peptide hormone receptors overexpressed in human
malignant neoplasms are potential targets for diagnostic scintigraphy and
radiotherapy. One such receptor is the
neuropeptide Y (NPY) receptor, mediating primarily feeding behavior in the brain but shown recently to play a role in
breast cancer. In this study, the presence of NPY receptors was evaluated in another group of gynecological
tumors, namely ovarian
tumors, using in vitro receptor autoradiography with (125)I-labeled
peptide YY and receptor subtype selective analogs. Remarkably, all 10 investigated
inhibin-expressing
granulosa cell tumors, Leydig cell
tumors, and
Sertoli-Leydig cell tumors expressed NPY receptors. In contrast, receptors were found in only seven of 22 ovarian
adenocarcinomas (32%). Pharmacological characterization of the expressed NPY receptor subtypes in the various
tumors revealed the presence of Y1, Y2, or both. In addition, Y1 receptors were observed in intra- and peritumoral blood vessels as well. NPY receptors were not expressed in three ovarian
adenomas, three borderline
tumors, four
fibromas and fibrothecomas, and one
dysgerminoma. This is the first time that NPY receptors are described in human ovarian tissue. They may play a role in the pathogenesis and also in the pathophysiology of ovarian
malignancies. Moreover, the high incidence and density of NPY receptors in
sex cord-stromal tumors suggest that these receptors represent a new potential target for the diagnostic and therapeutic administration of NPY analogs in these
tumors.