Evidence of involvement of the PLAG1 gene in lipoblastomas

Previous cytogenetic studies have demonstrated that the majority of lipobla stomas show rearrangements, in particular translocations and insertions, wi th breakpoints in 8q11-13. Here we present evidence for involvement of the developmentally regulated zink finger gene PLAG1 in these rearrangements, N orthern blot and RT-PCR analyses revealed overexpression of PLAG1 in two li poblastomas. Using immunohistochemistry, expression of the PLAG1 protein wa s also demonstrated in tissue sections from two lipoblastomas, one of which had a t(3;8)(q13.1;q12) translocation and the other a t(1;6)(q42;p22) tran slocation. Since no aberrant PLAG1 transcripts could be detected, it is lik ely that the gene may be activated by promoter swapping/substitution or alt ernatively by an as yet unknown mechanism. Our findings indicate that PLAG1 activation is a recurrent event in lipoblastomas and that PLAG1 is likely to be the target gene on chromosome 8 in these tumors.