Overexpression of mammaglobin B in epithelial ovarian carcinomas.
OBJECTIVE
Mammaglobin B is a uteroglobin gene family member recently found highly differentially expressed in serous papillary ovarian cancer by gene expression profiling. In order to evaluate its potential as a novel ovarian cancer biomarker, in this study we quantified and compared Mammaglobin B expression in various histologic types of epithelial ovarian carcinomas (EOC).


METHODS
Mammaglobin B expression was evaluated by real-time PCR and/or immunohistochemistry in fresh-frozen biopsies and paraffin-embedded tissues derived from a total of 137 patients including 69 primary EOC with different histologies, 28 serous papillary omental metastasis, 8 borderline tumors, 26 benign cystadenomas and 14 normal ovaries.


RESULTS
High levels of Mammaglobin B gene expression were detected in 100% (68 out of 68) of the ovarian cancer biopsies tested by real-time PCR. In contrast, normal human ovarian surface epithelium (HOSE) expressed negligible levels of Mammaglobin B mRNA (EOC versus HOSE, p<0.01). Although Mammaglobin B gene expression levels were higher in endometrioid, mucinous and undifferentiated tumors when compared to serous papillary tumors, clear cell tumors and those with mixed histology, these differences were not statistically significant. In agreement with real-time PCR results, EOC were found to express significantly higher levels of Mammaglobin B protein when compared to normal ovaries and benign cystadenomas (p<0.01). However, only 29 out of 68 (42%) of the EOC samples found positive for Mammaglobin B by real-time PCR showed immunoreactivity by IHC.


CONCLUSIONS
Mammaglobin B gene is highly expressed in EOC and may represent a novel molecular marker for multiple histological types of ovarian cancer. Additional studies to evaluate the clinical utility of Mammaglobin B as a diagnostic and/or therapeutic target in ovarian cancer are warranted.
Tassi
Renata A
RA
Division of Gynecologic Oncology, University of Brescia, Brescia, Italy.
Bignotti
Eliana
E
Rossi
Elisa
E
Falchetti
Marcella
M
Donzelli
Carla
C
Calza
Stefano
S
Ravaggi
Antonella
A
Bandiera
Elisabetta
E
Pecorelli
Sergio
S
Santin
Alessandro D
AD
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics; D045744:Cell Line, Tumor; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D060788:Mammaglobin B; D008875:Middle Aged; D009185:Myelin Proteins; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D010051:Ovarian Neoplasms / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D016133:Polymerase Chain Reaction; D011510:Proteolipids; D060765:Secretoglobins; D014598:Uteroglobin / Q000096:biosynthesis* / Q000235:genetics
D014408:Biomarkers, Tumor; D060788:Mammaglobin B; D009185:Myelin Proteins; D009363:Neoplasm Proteins; D011510:Proteolipids; C556467:SCGB2A1 protein, human; D060765:Secretoglobins; D014598:Uteroglobin