Expression of heat shock protein (HSP70) in oral lichen planus and non-dysplastic oral leucoplakia.

The purpose of this study was to investigate the expression of heat shock protein (HSP70) in oral non-dysplastic leucoplakia and in relation to the clinical and pathological features of oral lichen planus. The expression of HSP70 was assessed in the epithelial compartment of normal mucosa (n = 5), oral lichen planus (n = 28) and benign leucoplakia (n = 11) using an immunohistochemical method. The immunostaining intensity distribution (IID) index was used to quantify the positivity of the staining. There was no association between HSP70 overexpression and clinical presentation of oral lichen planus. Oral lichen planus patients showed no statistically significant differences in the depth of the inflammatory infiltrate when expression of HSP70 was considered (X(i)- X(j) = 42.30; 95% confidence interval (95% CI) = -120.87-205.48). No statistically significant differences were identified in terms of HSP70 expression between oral lichen planus and normal buccal mucosal specimens (X(i)- X(j) = 4.07; 95% CI = -0.53-8.67). The IID index score for HSP70 expression in leucoplakia specimens was significantly higher than the one of the oral lichen planus group (X(i) - X(j)= 5.11; 95% CI = 1.73-8.48). It is concluded that there are no statistically significant differences in HSP70 expression between oral lichen planus and normal buccal mucosal specimens, suggesting that HSP70 does not play an obvious part in the pathogenesis of oral lichen planus. The expression of HSP70 was significantly higher in oral leucoplakia than in oral lichen planus, possibly because of differences in cellular activity or cell proliferation.