Abstract

Although there is still controversy to the relationship between c-erbB-2 protein expression and prognosis of the gastric carcinoma, there were many reports about the poor prognosis with the expression of c-erbB-2 in gastric carcinoma. The mechanisms underlying this phenomenon are not known. However several possibilities such as acquired resistance to 5-Fluorouracil(5-FU) and resistance to the host immune system were suggested. So we performed this study to evaluate whether c-erbB-2 expression can alter the natural killeriNK) cell cytotoxic activity. Using single cell suspensions from primary gastric cancer tissues and malignant ascites due to stomach cancer, the immunohistochemical reactivity to c-cerB-2 protein was examined and we performed the tests for NK cell cytotoxic activity. The c-erbB-2(+) cancer cells were significantly more resistant to NK cell cytotoxic activity than c-erbB-2( ) cancer cells. However there was no significant difference in the resiatance to NK cell cytotoxic activity according to their immunohistochemical staining intensities. These results suggest that the resistance to the NK cel1 cytotoxicity may be one of the possi- ble mechanisms of the poorer prognosis of the c-erbB-2(+ ) gastric cancers.

• Keywords: c-erbB-2 protein, Gastric cancer ce11, NK cell cytotoxicity