Heat shock protein (HSP70) as a marker of epithelial dysplasia in oral dysplastic lesions: A clinicopathological study

OBJECTIVE: In the present study, expression of heat shock protein (HSP70) was evaluated and compared in oral dysplastic lesions, in particular leukoplakia (study group) and in normal mucosal tissues (control group). Additionally, correlation of HSP70 expression with clinical disease status was investigated. SUBJECTS AND METHODS: A total of 60 fresh tissue specimens were obtained from the oral cavity, consisting of 30 dysplastic cases and 30 normal mucosal tissues. The presence of epithelial dysplasia and its histologic grading was evaluated. Immunohistochemistry was carried out with the monoclonal HSP70 antibodies and expression of cytoplasmic HSP70 within the epithelium was compared between dysplastic and normal mucosal samples using Student's t-test. RESULTS: Expression of HSP70 was detected in 93% of the oral dysplastic tissues and 20% of the normal mucosal tissues. Statistical significant difference in the HSP70 expression was seen between oral dysplastic tissues and normal oral mucosal tissues (P < 0.000). The interexaminer reliability was 93.3%. Statistical significant difference was seen in the HSP70 expression between controls and different grades of dysplasia (mild, moderate and severe). There was no relationship of HSP70 expression with clinical parameters like age, sex, site of the lesion, history of adverse habits and duration of adverse habits. CONCLUSION: In the present study, HSP70 activity was significantly higher in oral dysplastic (leukoplakia) group than in the control group. Further, as the grade of dysplasia increased, the staining intensity and/or distribution increased, indicating that enhanced HSP70 expression occurs during oral carcinogenesis. Hence, it is concluded that increased HSP70 immunoexpression could be an objective marker for the presence of epithelial dysplasia.