Immunohistochemical distribution of heat shock protein 47 (HSP47) in scirrhous carcinoma of the stomach.

BACKGROUND: The aim of the present study was to examine the immunohistochemical distribution of the 47-kDa heat shock protein (HSP47) to enhance the understanding of the mechanisms involved in stromal fibrosis, which accompanies cancer infiltration in scirrhous carcinoma of the stomach.
MATERIALS AND METHODS: In vitro gastric cancer models were prepared by collagen gel cultures using three different human gastric cancer cell lines (KATO-III, MKN-74, MKN-45) and a human fibroblast cell line (TIG-101). Tumor tissues were obtained from ten patients with early gastric cancer (5 scirrhous carcinoma; 5 non-scirrhous carcinoma) and three patients with advanced scirrhous gastric cancer. The gels and the tissues were immunostained by a monoclonal antibody against human HSP47 and then examined by light and electron microscopy.
RESULTS: The staining intensity of the fibroblasts was stronger than that of cancer cells in both the culture models and patient tissues. Moreover, the number of fibroblasts in scirrhous gastric cancer was significantly greater than that in non-scirrhous gastric cancer (p = 0.0004). In addition, the discharge of HSP47 was observed in the extracellular matrix as granular deposits of staining.
CONCLUSION: These findings indicate that fibroblasts predominantly produce stromal collagen and may play an important role in the development of stromal change in scirrhous gastric cancer. Further studies are required to elucidate the significance of HSP47 in the development of new clinical approaches for treating scirrhous gastric cancer.