Intraepithelial expression of perlecan, a basement membrane-type heparan sulfate proteoglycan reflects dysplastic changes of the oral mucosal epithelium.
BACKGROUND
Intercellular deposition of perlecan, a major heparan sulfate proteoglycan (HSPG) of the basement membrane, is known to result in characteristic stellate reticulum-like structures in ameloblastomas or tooth germs. Although enlargement of the intercellular space is one of the histological characteristics of epithelial dysplasia of oral mucosa, the mode of expression of perlecan is poorly understood in these epithelial lesions.


METHODS
Eighty-two biopsy specimens consisting of normal and hyperplastic epithelium, epithelial dysplasia, and squamous cell carcinomas were examined for both perlecan core protein and heparan sulfate (HS) chains by immunohistochemistry and in situ hybridization.


RESULTS
In normal and hyperplastic epithelium, perlecan core protein and HS chains were localized in the cell border of parabasal cells and lower prickle cells, and HS chains were also found in basal cells. With an increase in the severity of epithelial dysplasia, the core protein was heavily and extensively deposited in the interepithelial space as well as in the cytoplasm of epithelial cells from the basal to the surface layers. Its gene expression was confirmed in the cells around the protein deposits. On the other hand, HS chains were enhanced in mild dysplasia, but decreased in moderate and severe dysplasias. In squamous cell carcinomas, either the core protein or HS chains were found scarcely in tumor cells but abundantly in the stromal space.


CONCLUSIONS
The findings indicate that perlecan is localized in the intercellular space of the oral epithelia, and that it is over-expressed in dysplastic epithelial cells and is deposited in their interepithelial space, which results in the histology of reduction of cellular cohesion.
Ikarashi
Terué
T
Division of Oral Pathology, Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
Ida-Yonemochi
Hiroko
H
Ohshiro
Kazufumi
K
Cheng
Jun
J
Saku
Takashi
T
D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D004848:Epithelium / Q000737:chemistry / Q000473:pathology; D005110:Extracellular Space / Q000737:chemistry*; D019812:Heparan Sulfate Proteoglycans / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D006965:Hyperplasia / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009061:Mouth Mucosa / Q000378:metabolism / Q000473:pathology; D009062:Mouth Neoplasms / Q000378:metabolism*
D019812:Heparan Sulfate Proteoglycans; C071927:perlecan