INTRODUCTION: Gastric cancer is one of the commonest cancers in our country being responsible for a high mortality rate. Recently, the expression of p53 and amplification of c-erb-B2 gene have been described in gastric carcinoma. The relevance and biological significance of these findings are not established yet. OBJECTIVE: The authors investigated p53, c-erb-B2 immunohistochemical expression in 482 cases of gastric carcinomas. MATERIAL AND METHODS: Tissue microarray (TMA) blocks were designed using replicate samples of paraffin-embedded tissue from 482 gastric carcinomas. Sections were stained with HE, and antibodies to p53 and c-erb-B2. Cases were considered p53 positive if nuclear staining was detected in > 10% of the tumor cells. Cases were assessed c-erb-B2 positive if the entire circunference of the cell membrane was stained in > 10% of the tumor cells. RESULTS: Overall expression of p53 and c-erb-B2 was observed in 30% and 12% of gastric carcinomas cases, respectively. Relationship with intestinal type of gastric carcinomas and expression of c-erb-B2 was shown (p < 0.001), and expression of p53 was observed in tumors larger than 5cm (p = 0.003). There was not significant difference in survival curves of patients with gastric cancer in relation to the expression of these markers. CONCLUSION: Intestinal type of gastric carcinomas in our country are more frequently positive for c-erb-B2 than diffuse type. The expression of p53 is associated with tumor size. The TMA is a valid and efficient way to study immunohistochemical markers, having a high correlation with the full section.
Gastric cancer; p53; c-erb-B2; Immunohistochemistry; Tissue microarray
