Loss of imprinting in hepatoblastoma.
We and others have described loss of imprinting (LOI) of the insulin-like growth factor II (IGF2) gene in 70% of Wilms' tumors (WT), an embryonal kidney tumor, and we have also found LOI of the H19 gene in 29% of WTs. In WT, LOI of IGF2 is coupled to down-regulation of H19. LOI of IGF2 has subsequently been described in a second embryonal neoplasm, rhabdomyosarcoma. However, the hypothesis that LOI is a general feature of embryonal tumors is challenged by a report of absence of LOI in three hepatoblastomas (S. M. Davies, Cancer Res., 53: 4781-4783, 1993). We identified five hepatoblastomas informative for a transcribed polymorphism of the IGF2 gene. One tumor showed LOI of IGF2, in contrast to the previous report. That tumor also showed LOI of H19, further documenting a role for this gene in imprinting disturbances in cancer. However, in contrast to WT, LOI in hepatoblastoma was not associated with down-regulation of H19. Thus, IGF2 and H19 expression can be uncoupled in tumors with LOI.
Rainier
S
S
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Dobry
C J
CJ
Feinberg
A P
AP
D000483:Alleles; D002648:Child; D015536:Down-Regulation / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology; D018392:Genomic Imprinting; D018197:Hepatoblastoma / Q000235:genetics*; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics; D008113:Liver Neoplasms / Q000235:genetics*; D011110:Polymorphism, Genetic
D007335:Insulin-Like Growth Factor II