MUTATIONS OF THE APC GENE OCCUR DURING EARLY STAGES OF GASTRIC ADENOMA DEVELOPMENT

Mutations of the adenomatous polyposis coli (APC) gene have recently b een shown to play an important role in colorectal tumorigenesis. We in vestigated mutations of the APC gene in 30 gastric adenomas obtained e ndoscopically. Mutations of the APC gene were examined by polymerase c hain reaction-single-strand conformation polymorphism analysis followe d by sequencing of the polymerase chain reaction products. Mutations w ere detected in 20% (6 of 30) of gastric adenomas. In addition, deleti on of the remaining allele that subsequently Led to complete inactivat ion of the APC gene was confirmed in one-half (3 of 6) of the tumors w ith APC gene mutations. Sequencing analysis confirmed that the mutatio ns resulted in truncation of the gene products or in an amino acid cha nge. The incidences of mutations of the APC gene remained constant reg ardless of the size or degree of histological atypia. Our observations suggest that mutations of the APC gene, similarly to those in colorec tal tumorigenesis, occur during the early stages of gastric adenoma de velopment.