Immunohistochemical Analysis of the Expression of Cathepsin D in Human Gastric Adenocarninoma

Abstract

PURPOSE: Cathepsin D is an acidic lysosomal proteinase involved in intracellular protein turnover. Increased levels of this enzyme have been reported to be indicators of aggressive tumor behavior in some human tumors. In gastric cancer, increased expression of cathepsin D has been reported to be an independent prognostic factor. MATERIALS AND METHODS: We used standard immunohistochemical techniques on formalin- fixed, paraffin-embedded tissues to examine the expression of the cathepsin D in fifty five gastric adenocarcinomas. And we compared these with other indicators of aggressive tumor behavior including stage of disease, tumor size, lymphatic invasion, neural invasion, Lauren classification, disease recurrence and survival. RESULTS: Positive granular cytoplasmic staining for cathepsin D was detected in 100% of the tumors and strongly positive staining was found in 53%. However, the intensity of the staining varied from cell to cell in the same carcinoma tissue as well as among samples. Positive staining also was seen in normal foveolar epithelial cells, parietal cells, macrophages and ganglion cells. Our results did not show any correlation between the expression of cathepsin D and other indicators of aggressive tumor behavior. But the group having more intensely stained margins showed the tendency to frequent lymphatic invasion. CONCLUSION: We conclude that the results obtained using polyclonal antibodies to cathepsin D do not support the prognostic usefulness of immunohistochemical analysis of this proteinase in tumor cells in human gastric adenocarcinoma, but this study may offer some useful indicator for further pathophysiological studies on gastric adenocarcinoma.