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 stres ses are known to play a major role in oesophageal squamous cell carcinoma d evelopment. Our goal was to evaluate whether changes in stress-induced 27-k Da heat shock protein (HSP27) expression could be demonstrated during oesop hageal carcinogenesis. Methods and results: HSP27 expression was studied using immunohistochemistr y on formalin-fixed, paraffin-embedded tissue sections from 21 oesophageal squamous cell carcinomas occurring in smokers and/or alcohol abusers. Oesop hagus from healthy patients (controls) (five), chemical (eight) and infecti ous oesophagitis (six) were also included in the study. In normal oesophagu s, 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 oes ophageal mucosa from smoking and/or drinking patients adjacent to invasive carcinoma, the distribution of the protein is patchy and irregular. In mali gnant areas, HSP27 protein expression increases drastically from dysplastic lesions to invasive carcinoma, being highest in the less differentiated ar eas. Conclusions: In human oesophagus, HSP27 expression is induced by various st resses but alcohol and tobacco generate focal perturbations in the stress r esponse. Tumour immunoreactivity for this protein increases with the anapla sia of the tumour, as in some other tumours in which it is considered to pl ay a role in drug resistance. To our knowledge, these data have not been pr eviously described for oesophageal squamous cell carcinoma.