Differential expression of Mr 70,000 heat shock protein in normal, premalignant, and malignant human uterine cervix.

Transformed cells differ from normal cells in their pattern of heat shock protein expression. Here, we report differential expression of a Mr 70,000 heat shock protein (HSP70) in squamous cell carcinomas of the uterine cervix compared to normal or premalignant uterine cervix. Expression of HSP70 was measured using a mouse mAb against HSP70 by an ELISA. A significant increase in the level of expression of HSP70 was observed in fresh tumor cells as compared to normal or dysplastic ones (P < 0.001). The induction of HSP70 in tumor cells subjected to hyperthermia was less than that in normal or premalignant cells. Strong cytoplasmic and nuclear immunostaining was observed in cancerous tissues using anti-HSP70 mAb, biotinylated rabbit antimouse immunoglobulins, avidin combined in vitro with biotinylated horseradish peroxidase, and diaminobenzidine tetrachloride. HSP70 immunostaining was not detected in normal or dysplastic tissue sections. The results were confirmed by immunoprecipitation using anti-HSP70 mAb. These results are the first demonstration of overexpression of HSP70 in squamous cell carcinomas of the uterine cervix as compared to that in dysplastic or normal uterine cervix cells. We conclude that tumor cells differ from normal cells in their pattern of HSP70 expression, and increased levels of HSP70 correlate with an increase in tumor size.