The comparative evaluation of CK17 expression in histologic and cytological sections of oral squamous-cell carcinoma using immunohistochemistry.

BACKGROUD: Squamous-cell carcinoma of the mouth accounts for 90% of all oral cancers and despite advances in treatment methods, its 5-year survival rate is reported to be about 68%. This is due to the late diagnosis of the disease and its resistance to radiotherapy and chemotherapy treatments. One of the methods for diagnosing oral lesions is exfoliative cytology, which is a noninvasive method and can be easily carried out in a dental office. AIM: The purpose of this study is to find a method that in addition to being fast, accurate and less aggressive has high value and a good degree of accuracy for diagnosis of oral squamous-cell carcinoma. MATERIALS AND METHODS: In this descriptive-analytical study, 14 patients who were diagnosed with oral squamous-cell carcinoma and 14 specimens from exfoliative cytology of the same tissue before surgery were examined. Immunohistochemically stained specimens were examined by two pathologists simultaneously. Next, five nonoverlapping sections with magnification (×400) and the number of cells stained with the cytokeratin marker 17 are counted and the average percentage of each slide is determined. One-sample t-test is used to analyze the data and significance level in tests is considered 0.05. RESULTS: In examining the diagnostic value of cytology, we concluded that out of 280 affected cells, 211 cells were stained. Therefore, the sensitivity of cytology in the diagnosis of squamous-cell carcinoma of the mouth is 75.4%. In other words, cytology correctly identifies 75.4% of affected cells as affected. Also, the positive predictive value of cytology was 100%.