Expression of growth hormone-releasing hormone in human primary endometrial carcinomas

Abstract

Background: Hypothalamic GH-releasing hormone (GHRH) regulates GH release from the pituitary, but an ectopic production of GHRH has been detected in various non-hypothalamic tissues, especially cancers. Objective: To investigate whether endometrial tumors produce GHRH. Methods: Twenty-four endometrioid, three serous papillary (SP), three mixed type endometrioid/ serous papillary adenocarcinomas and one malignant mixed Müllerian tumor (MMMT) were assessed for GHRH immunoreactivity by the polyclonal anti-rabbit antibody SV95 and for the expression of GHRH mRNA by in situ hybridization using an oligonucleotide probe. Results: Increased GHRH immunoreactivity was detected in 15 out of 24 (63%) of the endometrioid tumors, including two out of three (66%) of the mixed type endometrioid/serous adenocarcinomas but not in the three SP or the MMMT tumor. Cytoplasmic staining was detected in all positive cases, while in three of them strong nuclear localization of GHRH was also revealed. In situ hybridization indicated the presence of GHRH mRNA in six cases, all characterized as positive for GHRH immunoreactivity. Conclusion: GHRH is expressed in a subset of endometrial tumors, of the endometrioid type in particular. A paracrine/autocrine role for GHRH in the development of the disease should be considered.