Overexpression of the heat shock protein HSP70 family and p53 protein and prognosis for patients with gastric cancer

Abstract

The cell synthesis of heat shock proteins is increased by a variety of environmental and pathophysiological stressful conditions. The 70-kD heat shock protein family (HSP70 family) which constitutively expresses hsc70 and heat-inducible hsp70 is thought to be involved in protein-protein interactions, including oncogene products. We investigated the HSP70 family expression and biological behavior of gastric cancer, and its relation to p53 overexpression. Expressions of HSP70 and p53 in 164 primary gastric tumors were determined immunohistochemically. Exploratory data were analyzed on a set of 164 primary gastric cancers, and we constructed in prognostic significance of the HSP70 expression level and the relation to p53 overexpression. Expression of HSP70 (hsc70 and hsp70) were detected in nuclei and/or cytoplasm of cancer cells. Western blotting analysis showed that hsc70 and hsp70 were both expressed in five gastric cancer cell lines. Immunohistochemically stained positive cells of HSP70 varied from 0 (very weak) to 100%, in each case. The median level of positive cell rate was 19.0%. A HSP70 expression of over 19.0% was related to the differentiated tissue type of gastric cancer, but not to other clinicopathological factors. There was no difference in survival rates in subjects with higher and lower groups of HSP70 expression. HSP70 expression was also not related to p53 overexpression in the nuclei and p53 overexpression-related poorer prognosis. Our findings show that the expression of HSP70 is not associated with tumor advance-related characteristics or with the prognosis of gastric cancer. Measurements of HSP70 expression do not appear to be a useful prognostic marker.