Increased expression of high but not low molecular weight heat shock proteins in resectable lung carcinoma

Strong expression of high-molecular-weight (HMW) heat-shook proteins (HSP) by lung carcinoma has been documented using immunohistochemistry. Far less is known about the expression of low-molecular-weight (LMW) HSP in lung can cer. We compared the quantitative expression of HMW (HSP-60, HSP-70) and LM W (HSP-27, ubiquitin) HSP in tumor and non-tumor lung tissue obtained from 47 patients undergoing surgical resection of lung carcinoma. HSP levels wer e determined in cell lysates from tissue samples by ELISA using streptavidi n-biotin technology. Results were normalized to total protein content measu red by spectrophotometry. Compared to disease-free lung tissue, tumor tissu e samples showed higher levels of both HSP-60 (median value: 227 pg versus 96 PS per mg protein (P < 0.001 by Wilcoxon Rank test for paired data) and HSP-70 (median value: 525 ng versus 401 ng per mg protein (P = 0.01 by Wilc oxon Rank test for paired data). Tumor and tumor-free tissues show similar levels of ubiquitin and HSP-27. Neither the survival rate nor the histologi c type and extent of cancer are correlated with the observed differences in HSP-60 and HSP-70 expression (P > 0.1 by one way analysis of variance for repeated measures with one between subject factor). Our data confirm, on a quantitative basis, the increased expression of HSP-60 and HSP-70 in non-sm all-cell lung carcinoma. However, no prognostic value was found to be assoc iated with this over-expression. In contrast, LMW stress proteins such as u biquitin and HSP-27, although implicated in cellular processes potentially related to malignant transformation, show Ilo increased expression in lung carcinoma. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.