Cytokeratin 18 & 19 Expression in Normal and Lesional Mucosa

Cytokeratins(CK) are structural proteins of epithelial cells. Changes in cytokeratin expression have been observed during neoplastic transformation. It is interesting to find biomarkers such as cytokeratin for detection of neoplastic transformation in precancerous lesions and for early detection of squamous cell carcinoma. Objectives: To evaluate cytokeratin 18 & 19 expression in normal mucosa, lichen planus and squamous cell carcinoma. Methods: Thirty cases each of normal mucosa, lichen planus and squamous cell carcinoma were retrieved from the archives of the Department of Oral Diagnosis, Khon Kaen University. Tissue sections were stained with antibodies to cytokeratin 18 & 19. Immunoreactivity was evaluated by counting of cells. CK labeling index was calculated by dividing the number of positively stained cells x 100 by total number of cells counted. Results: 9 out of 30 (30.0%) normal mucosa, 5 out of 30 (16.7%) lichen planus and 4 out of 30 (13.3%) squamous cell carcinoma demonstrated positive staining for CK18. Squamous cell carcinoma showed the highest mean CK18 labeling index, followed in descending order by normal mucosa and lichen planus, respectively. Twenty three out of 30 (76.7%) normal mucosa, 9 out of 30 (30.0%) lichen planus and 1 out of 30 (3.33%) elicited positive staining for CK19. Normal mucosa elicited the highest mean CK19 labeling index, followed in descending order by lichen planus and squamous cell carcinoma, respectively. Conclusions: CK19 might be a good candidate to be included in a panel of antibodies for detecting malignant transformation of oral mucosa into squamous cell carcinoma. Further studies with other precancerous lesions with larger-scaled studies as well as a wider variety of antibodies should be carried out before a panel of antibodies capable of detecting malignant transformation into squamous cell carcinoma can be established.

This research was supported by Research Fund, Faculty of Dentistry, Khon Kaen University.