Expression of integrin alpha9 subunit and tenascin in oral leukoplakia, lichen planus, and squamous cell carcinoma.
OBJECTIVE
Integrin alpha9 subunit is a member of beta1 integrin family and binds tenascin (TN). It is expressed by stratified squamous epithelium and may be associated with cell differentiation and growth. We studied if the expression of alpha9 integrin and TN is altered in leukoplakia, lichen planus, and squamous cell carcinoma (SCC).


METHODS
Frozen sections of tissue samples obtained from normal human keratinized (16 subjects) and non-keratinized (three subjects) oral mucosa, oral leukopakias with dysplasia (19 subjects), reticular type lichen planus (nine subjects), or oral mucosal SCC (23 subjects) were stained immunohistochemically with antibodies against alpha9 integrin and TN.


RESULTS
In contrast to its most prominent localization at the cell membranes of the basal epithelial cells in the normal mucosa, alpha9 integrin was localized in a more diffuse pattern with focal loss of expression at the epithelial cell membranes in leukoplakic dysplasia, lichen planus, and SCC. In some areas of SCC, alpha9 integrin localized throughout all cell layers of the tumor epithelium. In most areas, alpha9 integrin colocalized with TN but in heavily inflamed areas there was focal loss of TN and alpha9 integrin at the basement membrane zone.


CONCLUSIONS
The findings show that alpha9 integrin expression is altered in leukoplakic dysplasia, lichen planus, and SCC.
Häkkinen
L
L
University of British Columbia, Faculty of Dentistry, Department of Oral Biological and Medical Sciences, Vancouver, B.C., Canada.
Kainulainen
T
T
Salo
T
T
Grenman
R
R
Larjava
H
H
D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D039001:Integrin alpha Chains; D016023:Integrins / Q000032:analysis / Q000378:metabolism*; D007972:Leukoplakia, Oral / Q000378:metabolism*; D017676:Lichen Planus, Oral / Q000378:metabolism*; D009061:Mouth Mucosa / Q000378:metabolism; D009062:Mouth Neoplasms / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000032:analysis / Q000378:metabolism*; D019063:Tenascin / Q000032:analysis / Q000378:metabolism*
D039001:Integrin alpha Chains; D016023:Integrins; D009363:Neoplasm Proteins; D019063:Tenascin; C084613:integrin alpha9