Heterogeneity of p53 mutational status in the superficial spreading type of early gastric carcinoma.

Abstract

The superficial spreading type of gastric carcinoma may originate from either a single cellular clone or from several different clones; this issue remains controversial. Indeed, the p53 gene has been shown to play an important role in gastric carcinogenesis, but there have been only a few reports on the heterogeneity of gastric carcinoma with respect to the p53 gene. We analyzed seven cases of the superficial spreading type of gastric submucosal carcinomas (80 lesions; 10 to 17 per case) which showed different histological types and/or different p53 protein staining patterns. Direct sequences of polymerase chain reaction products were used for the analysis. p53 Gene heterogeneity in mucosal carcinoma lesions was detected in three cases. However, in all of the cases, the p53 mutational pattern was identical to that found in the submucosal carcinoma lesions. In the heterogeneous cases, the mutation in the submucosal carcinoma was one of the mutation patterns found among the mucosal carcinoma lesions. More precisely, the mutational pattern of both submucosal carcinoma lesions and the mucosal lesions located just above them, was identical. These data suggest that, with regard to the p53 gene, in some superficial spreading types of gastric carcinomas, there are various subclones in the mucosal carcinoma; one of these subclones becomes predominant through clonal selection, and, thus, invades the submucosa.