Co-expression of the MDR1 gene and HSP27 in human ovarian cancer.

Heat-shock proteins seem to play a still undefined role in cancer. One of them particularly, the low molecular weight HSP27, seems to be involved in resistance to chemotherapy. This phenomenon has been reported in breast cancer cell lines, and the aim of this study was to investigate if it also takes place in clinical tumour samples from ovarian cancer patients. We studied ovarian carcinoma samples from 95 patients by means of immunohistochemistry for the overexpression of both the product of the multidrug-resistance gene (P-glycoprotein) and HSP27. The expression of the MDR1 gene in more than 50% of the tumour cells was associated with an almost significantly shorter survival of patients with stage II, III and IV tumours (p = 0.05), although intriguingly not with the response to chemotherapy. Tumours expressing the MDR1 gene, furthermore, also tended to co-express HSP27 (64.9% vs. 42.1%), and this difference was statistically significant (p = 0.026).