Study on the relationship between P-glycoprotein(P-gp) and C-erbB-2 expression in gastric carcinoma

Objective: To understand the relationship between C-erbB-2 and multidrug resistance (MDR) as well as its clini- cal significance. Methods: P-gp level was detected by flow cytometry and simultaneously to examine the C-erbB-2 expression level by immunohistochemistry assay in the operating samples. Their relationship was analyzed from 59 cases with gastric carcinoma. Results: The P-gp positive expression was 38/59 (64.4%) cases with gastric carcinoma. The C-erbB-2 positive expression was 21/59 (35.6%) cases with gastric carcinoma. From the analysis of the P-gp and C-erbB-2 relationship, which was involving, range in the gastric carcinoma, that involving two or three sites were more than the site one, in the cases with C-erbB-2 negative. Compared this two groups, there was a significant difference (P = 0.026). When the C-erbB-2 was positive, the P-gp expression had a significant difference (P = 0.04) in comparing the III–IV stage (lymph node metastasis) with I–II stage (without lymph node metastasis). The tumor’s size, differentiation degree, ages and sex were not related to the C-erbB- 2 and P-gp expression. Conclusion: High level of P-gp expression was related to the C-erbB-2 positive expression in clinical III–IV stage patient with gastric carcinoma (lymph node metastasis). It suggested that the double positive patient might be a poor prognosis. However, when the C-erbB-2 was negative expression, the clinical staging (with lymph node metastasis) was not related to the P-gp expression in gastric carcinoma patients.