Expression of heat shock protein 70 in oral epithelial dysplasia and squamous cell carcinoma

Heat shock proteins (HSPs) are overexpressed in a variety of human malignancies. They are involved in tumor cell proliferation, differentiation, invasion, metastasis, death, and immune system detection. HSP 70 has been shown to resist cytotoxicity in cancer cells and even enhance tumor development through an immune escape mechanism, suggesting that HSP70 may play a role in carcinogenesis. The aim of our study was to evaluate the role of HSP70 as a predictive marker for malignant transformation in oral epithelial dysplasia.

Thirty samples of epithelial dysplasia (10 mild dysplasia, 10 moderate dysplasia, and 10 severe dysplasia/carcinoma-in-situ cases), 10 samples of well-differentiated oral squamous cell carcinoma (OSCC), and 10 samples of normal oral mucosa were routinely processed, formalin-fixed, paraffin-embedded, and immunohistochemically examined for HSP70 expressions. To determine the statistical difference between two groups, a one-way analysis of variance (ANOVA) and the Mann-Whitney test were used.

HSP70 expression was high but not homogenous in normal mucosa. Dysplasia showed an initial drop, and the expression increased with increasing degrees of dysplasia. There was no statistically significant difference across various types of epithelial dysplasia. From dysplasias to well-differentiated carcinoma, HSP70 exhibited a considerable rise.

Overexpression of HSP70 in clinically suspicious and histologically established epithelial dysplasia may suggest a likelihood of transformation to well-differentiated OSCC and may have a prognostic value. However, more studies with a bigger sample size are needed to prove HSP70's role as a predictor.