Promoter switch: a novel mechanism causing biallelic PEG1/MEST expression in invasive breast cancer.

Abstract

We have previously reported on the biallelic expression of the imprinted PEG1/MEST gene in infiltrating carcinomas of the breast. Putative loss of imprinting (LOI) of PEG1/MEST has subsequently also been implicated in the aetiology of lung adenocarcinomas and colon cancer. Taking advantage of our previous study, identifying seven infiltrating carcinomas of the breast, displaying biallelic PEG1/MEST expression, we have analysed the allelic usage of the two alternative PEG1/MEST transcripts encoding isoforms 1 and 2, separately. In addition, expression levels of the two transcripts have been measured by real-time RT-PCR, in order to elucidate the mechanism behind the switch from monoallelic tr..