The results of surgical treatment for gastric cancer are apparently better in Japan than in Western countries. It has been proposed that this is because of a biological difference between the tumours in Japan and in the West. We have previously reported very similar frequencies of positive immunohistochemical staining for the c-erbB2 oncogene and mutant p53 proteins in British and Japanese gastric cancers, findings which do not seem to support the 'biological difference' hypothesis. We realized that these studies did not rule out differences in the mechanism of cancer progression which might show themselves by a different association between p53 and c-erbB2 expression and stage in the two populations. We therefore re-analysed our data to look for differences in the frequency of p53 and c-erbB2 expression in the British and Japanese populations. Comparison of fixed tissue from 88 British and 89 Japanese tumours showed no significant association of c-erbB2 or p53 with stage progression in either population. Logistic regression showed no difference between the two populations in the relationship between stage and oncogene expression. These results do not support the idea of biologically different cancers in Japan and Britain. Other possible explanations for the difference in results such as the stage migration effect, better efficacy of Japanese-style surgery, or a difference in the host resistance to cancer in the two countries should be considered.