Overexpression of the tyrosine phosphatase PTP1B is associated with human ovarian carcinomas.
OBJECTIVE
Our purpose was to determine whether protein tyrosine phosphatase 1B is overexpressed in ovarian cancers, possibly altering the balance of intracellular tyrosine phosphorylation.


METHODS
The expression of protein tyrosine phosphatase 1B was assayed in frozen sections from 54 human ovarian carcinomas and seven normal ovaries by immunochemical staining with monoclonal antibody AE4-2J, which is specific for protein tyrosine phosphatase 1B. The expression of protein tyrosine phosphatase 1B-specific messenger ribonucleic acid in tumors was determined by Northern analysis. The results were analyzed statistically by means of Fisher's exact test.


RESULTS
Minimal staining was observed in normal ovarian epithelium. In contrast, 43 of 54 (79.6%) tumors displayed increased protein tyrosine phosphatase 1B expression, which is statistically associated with malignancy. Overexpression was associated with the expression of the p185c-erbB-2, p170EGFR, and p165mCSFR growth factor receptor protein tyrosine kinases. Protein tyrosine phosphatase 1B messenger ribonucleic acid expression was inconsistently increased in tumor cells.


CONCLUSIONS
Increased expression of protein tyrosine phosphatase 1B in ovarian cancers that also express protein tyrosine kinases suggests that protein tyrosine phosphatase 1B may play a role in the growth regulation of ovarian cancers.
Wiener
J R
JR
Department of Obstetrics and Gynecology, Duke University Medical Center, Durham, NC 27710.
Hurteau
J A
JA
Kerns
B J
BJ
Whitaker
R S
RS
Conaway
M R
MR
Berchuck
A
A
Bast
R C
RC
D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007150:Immunohistochemistry; D010051:Ovarian Neoplasms / Q000201:enzymology*; D017027:Protein Tyrosine Phosphatases / Q000032:analysis* / Q000502:physiology; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis; D014407:Tumor Cells, Cultured
D020794:Receptor Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases