Objective: To evaluate the utility of immunohistochemical staining of p53 expression in endoscopic biopsy specimens in clinical practice.
Methods: Using a streptavidin-peroxidase (S-P) conjugate method with monoclonal p53 antibody Do-7, the expression of p53 was investigated immunohistochemically in 150 endoscopic biopsies and paired brushings from patients with benign and malignant gastric diseases. Among them, 22 cases with gastric carcinoma underwent the gastrectomy and the immunohistochemistry was repeated in the resected cancerous tissues of the same patient.
Results: p53 expression in endoscopic specimens was detectable in 35.7% cases of gastric carcinoma (n = 70), 5.9% of gastric polyps (n = 17), 16.7% of gastric mucosal dysplasia (n = 18) and 4.0% of chronic atrophic gastritis (n = 25), but no protein expression was observed in cases of chronic active gastritis (n = 20). In 22 patients with tumor resection, 8 (36.4%) were identified with p53 expression in endoscopic specimens before surgery, while 10 (45.5%) were identified with the same expression in surgical specimens, the real positive rate was 80.0%, no false positives were observed in endoscopic specimens. Furthermore, p53 expression in gastric carcinoma was closely correlated with clinical stage and lymph nodes involvement, but did not correlate with histologic type.
Conclusions: Assay of p53 by immunohistochemistry in endoscopic biopsy specimens and brushings is an easy and reliable technique to assess p53 status in gastric carcinoma, and thus could serve as a marker to foresee the prognosis in these patients and assist in the diagnosis of malignancy before surgery. It may also be a valuable marker in screening patients with high risk of gastric carcinoma.