Heat Shock Proteins 27, 70 and 90 Protein Expression in Gastric Adenocarcinoma: Prognostic, Predictive and Cellular Differentiation Significances

Gastric cancer is the second global leading cause of death from cancer and the most common gastrointestinal cancer in Iran. This condition is usually diagnosed at advance stages where treatment options are limited. Recently, heat shock proteins (HSPs) have been reported to be overexpressed in a wide range of malignancies and considered as promising candidate biomarkers and therapeutic targets for gastric adenocarcinoma. The aim of the present study was to compare HSPs protein expression between non-tumoral and tumoral sections from patients with gastric adenocarcinoma and determine HSPs protein expression correlation with histological stage, tumoral grade and prognosis.

Immunohistochemistry was used to assess the expression levels of HSP27, 70 and -90 proteins on both tumoral and non-tumoral (margin of tumor as control group) sections in 80 patients with gastric adenocarcinoma. Further analyses were histology, grade and stage of tumor (Tumor, node, and metastasis), HSPs expression level, clinicopathological significances, and survival rate.

The expression of HSPs was significantly increased in tumoral sections compared with non-tumoral sections (P<0.001). The HSP27 expression was correlated with tumors on the corpus of stomach (P=0.049). Patients younger than 63 years revealed higher expression levels of HSP70 (P=0.040). High expression levels of HSP90 were further assessed in well-differentiated and intestinal types of tumors (P=0.009 and P=0.019). Overexpressed levels of HSP27 and 90 were associated with the reduced survival rate of patients (P=0.017 and P=0.018).

HSP27 and HSP 90 are potential prognostic biomarkers of patients’ survival rate. Patients harboring positive HSP27 and HSP 90 expression display worse disease-free survival compared to those with negative HSP27 and HSP 90 expression. Differential expression of HSPs may play crucial roles in the initiation and progression of gastric cancer and can be exploited as future therapeutic targets.