ING1 and p53 tumor suppressor gene alterations in adenocarcinomas of the esophagogastric junction

The aim of this study was to characterize molecular alterations of the recently reported candidate tumor suppressor gene, ING1, and to explore the relationship between ING1 and p53 in a well-defined series of adenocarcinomas of the esophagogastric junction (AdEGJ). Polymerase chain reaction (PCR)-based assays were used to characterize ING1 and p53 alterations, relative to histologically normal esophageal mucosa. Two tumors were found to have ING1 mutations: one novel missense mutation (AGC(Ser)-->ATC(Ile)) at codon 147, and one silent mutation (TCG(Ser)-->TCA(Ser)) at codon 173. Reduced expression of the two major alternatively spliced ING1 messenger RNA variants, p47(ING1a) and p33(ING1b) was variable, but was reduced (1.2-10-fold) in 12 of 19 AdEGJs compared to normal esophageal epithelium. No association between p53 and ING1 alterations was apparent. We conclude that reduced ING1 expression is frequently associated with AdEGJ tumorigenesis, further supporting its role as a tumor suppressor gene, and that ING1 expression is independent of p53 status.