Expression of brx proto-oncogene in normal ovary and in epithelial ovarian neoplasms.
OBJECTIVE
We previously identified a protein, Brx, that interacted with estrogen receptor alpha. Sequence analysis determined that Brx is a novel member of the Dbl family of oncoproteins involved in signaling pathways that regulate cell growth. Because the Brx protein was found to be highly expressed in hormoneresponsive breast epithelium, the objective of this study was to determine whether Brx was expressed in both normal and neoplastic ovarian tissues.


METHODS
A polyclonal antiserum directed against the Brx protein was used to perform immunolocalization on sections from 5 normal ovaries and 20 ovarian neoplasms. Chromosomal localization of the brx gene was accomplished by means of fluorescence in situ hybridization. Northern and Western blot analyses were performed on extracts prepared from human ovaries.


RESULTS
Brx protein was localized to the cytoplasm of granulosa cells from mature graafian follicles, the corpus luteum, and islands of hilar cells in normal ovaries. In tumors with low malignant potential and ovarian carcinomas the neoplastic epithelium stained strongly for Brx protein. Northern and Western blot analyses, respectively, confirmed expression of Brx messenger ribonucleic acid and protein in normal ovary. Finally, the brx gene was localized to 15q25.


CONCLUSIONS
The proto-oncogene brx is expressed in specific normal human ovarian tissues and is also present in ovarian epithelial neoplasms.
Miller
B T
BT
Department of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
Rubino
D M
DM
Driggers
P H
PH
Haddad
B
B
Cisar
M
M
Gray
K
K
Segars
J H
JH
D054758:A Kinase Anchor Proteins; D048868:Adaptor Proteins, Signal Transducing; D015152:Blotting, Northern; D015153:Blotting, Western; D002277:Carcinoma / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D002884:Chromosomes, Human, Pair 15; D004848:Epithelium / Q000276:immunology / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D015778:Minor Histocompatibility Antigens; D015513:Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D010053:Ovary / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*
D054758:A Kinase Anchor Proteins; C085467:AKAP13 protein, human; D048868:Adaptor Proteins, Signal Transducing; C000715470:MAS1 protein, human; D015778:Minor Histocompatibility Antigens; D015513:Oncogene Proteins; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins