EXPRESSION OF EPIDERMAL GROWTH-FACTOR RECEPTOR FAMILY PROTEINS (EGFR,C-ERBB-2 AND C-ERBB-3) IN GASTRIC-CANCER AND CHRONIC GASTRITIS

The expression and coexpression of EGFR, c-erbB-2 and c-erbB-3 in 21 g astric cancers and 20 chronic gastritis was examined using immunohisto chemistry on fresh frozen tissues considering clinicopathological vari ables. Generally, gastric cancer patients showed a higher incidence of EGFR, c-erbB-2 and c-erbB-3 overexpression than the group with chroni c gastritis (81% and 43%; 38% and 45%; 35% and 20%,respectively), howe ver statistically significant differences were found only for EGFR exp ression (p=0.01). No association between immunoreactivity of all growt h factor receptors and the histopathological structure of gastric canc er was observed. EGFR and c-erbB-3 proteins were detected more frequen tly in patients with III/IV than in I/II of TNM stages, while c-erbB-2 overexpression was higher in I/II vs. III/IVstages. In chronic gastri tis with intestinal metaplasia and or coexisting carcinoma lesions, a higher frequency of the expression of studied proteins was observed in comparison with chronic gastritis without those alternations; however ,these differences were statistically insignificant. The percentage of positive cases with coexpression of two proteins was comparable in ga stric cancer and chronic gastritis (33% and 35%) but the simultaneous expression of all three receptors was evident only in gastric cancer ( 19%). Our results indicate that at least one or two members of EGFR re lated receptors could appear in the early stages of gastric tumorigene sis. The enhancement of c-erbB-2 and c-erbB-3 reactivity seems to coop erate with EGFR activation in the gastric cancer development. Our resu lts indicate the promotional rather than direct transformational role for EGFR supergene family; in gastric carcinogenesis.