COMPARISON OF P53 AND DNA CONTENT ABNORMALITIES IN ADENOCARCINOMA OF THE ESOPHAGUS AND GASTRIC CARDIA

This study examined the association between 17p allelic loss, p53 gene mutation, p53 protein expression and DNA aneuploidy in a series of ad enocarcinomas arising in the oesophagus and gastric cardia. 17p alleli c loss was detected in 79% (15 of 19) of oesophageal and in 83% (29 of 35) of gastric adenocarcinomas. p53 mutations were detected in 70% (1 4 of 20) and 63% (26 of 41) of oesophageal and of gastric adenocarcino mas respectively. Both tumour types were associated with a predominanc e of base transitions at CpG dinucleotides. In five cases of oesophage al adenocarcinoma, the same mutation was detected both in tumour and i n adjacent dysplastic Barrett's epithelium. Diffuse p53 protein expres sion was detected in 65% (13 of 20) and 59% (24 of 41) of oesophageal and of gastric tumours, respectively, and was associated with the pres ence of p53 missense mutation (Chi-squared, P < 0.0001). DNA aneuploid y was detected in 80% (16 of 20) of oesophageal and in 70% (28 of 40) of gastric tumours. No association was found between p53 or DNA conten t abnormalities and tumour stage or histological subtype. In conclusio n, this study detected a similar pattern of p53 alterations in adenoca rcinoma of the oesophagus and gastric cardia-molecular data consistent with the observation that these tumours demonstrate similar clinical and epidemiological features.