PROMOTER-SPECIFIC METHYLATION AND EXPRESSION ALTERATIONS OF IGF2 AND H19 ARE INVOLVED IN HUMAN HEPATOBLASTOMA

In earlier studies we found up-regulation of promoter P3 transcription and total igf2 expression with concomitant down-regulation of h19 exp ression in human hepatoblastoma (HB). In this study, we investigated t he methylation status of these 2 genes and their abnormal regulation i n 7 hepatoblastomas and 5 normal counterpart tissues. A specific part of the P3 region of igf2 was de-methylated in tumors with up-regulatio n of the promoter activity, A site-specific DNA hypermethylation in th e h19 5'-region was found in tumor tissues with concomitant down-regul ation of this gene, Therefore, abnormal methylation was found to be co rrelated with altered regulation of igf2 and h19 expression in human h epatoblastoma and may be involved in the genesis of this tumor. (C) 19 98 Wiley-Liss, Inc.