Integrated p53 histopathologic/genetic analysis of premalignant lesions ofthe esophagus

Esophageal carcinoma frequently occurs in patients with long-standing achal asia. Aim: To examine the role of p53 alterations and PCNA in patients with megaesophagus. Methods: Sections of four tumors, and corresponding adjacen t areas, from patients with achalasia due to Chagas' disease were examined by immunohistochemistry for p53 and PCNA proteins. Furthermore, 128 biopsie s from 16 advanced achalasic patients were prospectively collected and eval uated for grades of inflammation, hyperplasia, dysplasia and also for p53 a nd PCNA proteins. All specimens showing p53 immunoreactivity were topograph ically genotyped using microdissection, PCR amplification and direct sequen cing of p53 exons 5-8. Results: Diffuse strong immunoreactivity of p53 was observed in 2/4 tumors. In one patient, the adjacent mucosa also showed str ong p53. In the adjacent mucosa, the same areas showing p53 overexpression also had PCNA positive cells. In the prospective group, 7/16 (43.7%) patien ts or 53/128 (41.4%) biopsies expressed p53. The grade of inflammation was significantly correlated with the presence of positive p53, in patients, p = 0.004 and in biopsies, p < 0.00001. PCNA expression was found in the basa l layer of the mucosa, and increased PCNA was associated with p53 overexpre ssion, p = 0.00018. Genotyping detected mutation in exon 6, codon 213 RG, i n one patient (1/16, 6.2%). Conclusions: (1.) p53 alterations, overexpressi on and mutational change, are an early event in patients with achalasia; (2 .) The inflammation frequently seen in these patients appears to be associa ted with alterations of the p53 protein; (3.) Expression of the tumor suppr essor gene is increased in areas showing proliferation.