Claudin-1 immunohistochemistry for distinguishing malignant from benign epithelial lesions of prostate.
BACKGROUND
Claudins are a family of approximately 23 integral membrane tight junction (TJ) proteins that maintain cell polarity and paracellular barrier functions in epithelial and endothelial cells. Although Claudin-1 was demonstrated to be typically downregulated in various cancers, the precise expression patterns of this protein in normal and neoplastic tissues remain poorly characterized.


METHODS
Using immunohistochemistry, the expression of Claudin-1 was investigated in prostate tissue samples arranged in a tissue microarray (TMA) format and comprising elements of normal prostatic epithelium (n = 6), benign prostatic hyperplasia (BPH; n = 38), prostatic intraepithelial neoplasia (PIN; n = 11), and prostate adenocarcinoma (n = 48). The Claudin-1 expression pattern was compared with that of the basal cell-specific markers, p63, and HMW cytokeratin (34betaE12), by employing double-labeling techniques in conjunction with image analysis methods utilizing color deconvolution algorithms.


RESULTS
In benign prostatic epithelium, pronounced Claudin-1 expression was observed in the basal cell layer with no staining in luminal cells. Prostate adenocarcinoma specimens from 98% (47/48) patients lacked Claudin-1 immunostaining, and no cases contained >5% immunopositive tumor cells.


CONCLUSIONS
Claudin-1 immunohistochemistry should be considered for use as a new diagnostic tool for distinguishing malignant from benign lesions of the prostate.
Krajewska
Maryla
M
Burnham Institute for Medical Research, La Jolla, CA 92037, USA.
Olson
Allen H
AH
Mercola
Dan
D
Reed
John C
JC
Krajewski
Stan
S
D062445:Claudin-1; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D011469:Prostatic Diseases / Q000378:metabolism / Q000473:pathology*; D011470:Prostatic Hyperplasia / Q000378:metabolism / Q000473:pathology; D040081:Protein Array Analysis
C081876:CKAP4 protein, human; C568108:CLDN1 protein, human; D062445:Claudin-1; D008565:Membrane Proteins; D007633:Keratins