Tohoku J. Exp. Med., 2001, 193 (3)

Infrequent APC Mutations in Serrated Adenoma

REIKO DEHARI^1,2

Department of Internal Medicine, Tokyo University School of Medicine, Tokyo 112-8688, and Department of Pathology, Yamagata University School of Medicine, Yamagata 990-9585

In 1990, Longacre and Fenoglio-Preiser introduced “serrated adenoma (SA)” combining architectural and cytological features of hyperplastic polyp and adenomatous epithelium. It has been reported that intramucosal carcinoma occurs in 10% of SAs. Although there have been many reports on SAs, its histogenesis and natural history still remain unknown. To clarify the genetic changes in SA, APC mutations in 28 SAs, 4 adenocarcinomas in/with SAs, 12 tubular adenomas (TAs) and 10 adenocarcinomas in/with TAs were evaluated in the present study. After polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) analyses, gene mutations were confirmed by direct sequencing. No APC mutation was detected in adenocarcinomas in/with SAs, and only one SA without adenocarcinoma (3.8%) was found to be positive for APC gene mutation, whereas the mutations were found in 66.7% of TAs and in 50% of adenocarcinomas in/with TAs. The frequency of APC gene mutation in SAs was significantly lower than that in control sporadic TAs. These findings suggest that SAs are genetically different from TAs.

Keywords —— colorectum; serrated adenoma; APC; mutation; PCR-SSCP

© 2001 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2001, 193, 181-186

Address for reprints: Reiko Dehari, Department of Pathology, Yamagata University School of Medicine, Iida-Nishi 2-2-3, Yamagata 990-9585, Japan.