Gastric hyperplastic polyps are common and generally regarded as benign lesions, whereas gastric adenocarcinomas infrequently occur from gastric hyperplastic polyps. Although gastric hyperplastic polyps have received a lot of attention because of their association with malignant transformation, it remains unclear whether gastric hyperplastic polyps are neoplastic lesions that have sporadic genetic changes similar to colorectal hyperplastic polyps. We performed genome-wide analyses of two gastric adenocarcinomas with hyperplastic polyp components. The interface between "adenocarcinoma" and "hyperplastic polyp" components was fairly sharp, and the adenocarcinoma components had copy number alterations and TP53 mutations, whereas the hyperplastic polyp components had only single nucleotide polymorphisms, which were also found in adenocarcinoma components. We did not detect any somatic changes in the hyperplastic polyp components, even in genome-wide analyses, which was in contrast to the adenocarcinoma components. However, due to the small number of cases examined herein, further genetic analyses of more cases are needed.
Keywords: Adenocarcinoma; Array comparative genomic hybridization; Hyperplastic polyp; Malignant transformation; Targeted amplicon sequencing.