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Expression of apoptotic signaling proteins in leukoplakia and oral lichen planus: quantitative and topographical studies
Author(s) -
Tanda Naoko,
Mori Shiro,
Saito Keiichi,
Ikawa Kyoko,
Sakamoto Seizaburo
Publication year - 2000
Publication title -
journal of oral pathology and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 83
eISSN - 1600-0714
pISSN - 0904-2512
DOI - 10.1034/j.1600-0714.2000.290804.x
Subject(s) - oral lichen planus , leukoplakia , keratinocyte , apoptosis , biology , pathology , cancer research , pathogenesis , immunohistochemistry , oral mucosa , signal transduction , medicine , immunology , microbiology and biotechnology , cancer , cell culture , biochemistry , genetics
Although the pathogenesis of leukoplakia has been unclear, carcinogenic transformation is postulated to result from alterations of apoptotic signal transduction proteins in epithelial cells. The pathogenesis of oral lichen planus (OLP) has also been unclear, but apoptotic changes of the epithelial cells in OLP have been reported. In the present study, we used a histochemical approach to describe human keratinocyte‐expression of several apoptotic signaling proteins in leukoplakia, in OLP, and in normal oral mucosa as a control. Mucosal biopsies from patients with leukoplakia ( n =13), OLP ( n =10), and normal oral mucosa ( n =9) were frozen, sectioned and immunostained with monoclonal antibodies to wild‐type (wt) tumor suppressive protein p53, cyclin‐dependent kinase inhibitor p21 WAF1/CIP1 and the oncoproteins MDM2, and Bcl‐2. Apoptosis was assessed in all cases by the TUNEL method. MDM2 and Bcl‐2 expression in keratinocytes were quantitatively greater in leukoplakia than in OLP. Wt‐p53 and p21 WAF1/CIP1 expression was quantitatively greater in keratinocytes in OLP than in leukoplakia. Keratinocyte maturation appeared histologically normal in OLP, even though wt‐p53 and p21 WAF1/CIP1 were expressed in these cells. Altered keratinocyte maturation was seen in leukoplakia lesions expressing MDM2 and Bcl‐2. No significant difference for the number of apoptotic epithelial cells was observed between leukoplakia and OLP, in spite of the divergent outcomes of the apoptotic signaling proteins.