Genomic imprinting of IGF2 and H19 in human meningiomas.

A number of genes, including IGF2 and H19, are normally imprinted with preferential expression of the paternal or maternal allele, respectively. Loss of imprinting (LOI) of IGF2 and H19 is found in a number of tumours, suggesting that LOI of IGF2 and/or H19 may play an important role in tumorigenesis. The IGF2 gene codes for a fetal growth factor and the H19 gene is likely to act as an RNA with an antitumour effect. We investigated the imprinting status of IGF2 and H19 in human meningiomas. The normally imprinted IGF2 gene lacks imprint in the leptomeninges and choroid plexus of the brain. To examine the imprinting status of IGF2 and H19 in human meningiomas we used the ApaI polymorphism in exon 9 for the IGF2 gene and the AluI polymorphism in exon 5 for the H19 gene. In total, 24 meningiomas of WHO grade I, II and III were analysed. 15 meningiomas (63%) were informative for the ApaI polymorphism in the IGF2 gene. Monoallelic expression (MAE) for IGF2 was found in 11 out of 15 tumours (73%) which is in contrast to the lack of imprinting status of IGF2 in leptomeninges. Ten cases (42%) were heterozygous for the H19 gene and biallelic expression was found in 3 out of 10 meningiomas (30%). These results indicate that modulation of the imprinting status of IGF2 and H19 may play an important role for the development of meningiomas.