Overexpression of 27-kDa heat shock protein relates to poor histological differentiation in human oesophageal squamous cell carcinoma

Aims Various stress conditions such as heat, chemical and mechanical stresses are known to play a major role in oesophageal squamous cell carcinoma development. Our goal was to evaluate whether changes in stress-induced 27-kDa heat shock protein (HSP27) expression could be demonstrated during oesophageal carcinogenesis. Methods and results HSP27 expression was studied using immunohistochemistry on formalin-fixed, paraffin-embedded tissue sections from 21 oesophageal squamous cell carcinomas occurring in smokers and/or alcohol abusers. Oesophagus from healthy patients (controls) (five), chemical (eight) and infectious oesophagitis (six) were also included in the study. In normal oesophagus, the protein is present only in the upper epithelial layers. In contrast, in chemical or infectious oesophagitis its expression is strong and occurs in all the epithelial layers including the basal layer. In non-tumoral oesophageal mucosa from smoking and/or drinking patients adjacent to invasive carcinoma, the distribution of the protein is patchy and irregular. In malignant areas, HSP27 protein expression increases drastically from dysplastic lesions to invasive carcinoma, being highest in the less differentiated areas. Conclusions In human oesophagus, HSP27 expression is induced by various stresses but alcohol and tobacco generate focal perturbations in the stress response. Tumour immunoreactivity for this protein increases with the anaplasia of the tumour, as in some other tumours in which it is considered to play a role in drug resistance. To our knowledge, these data have not been previously described for oesophageal squamous cell carcinoma.