Expression of HMGA2-LPP and LPP-HMGA2 fusion genes in lipoma: identification of a novel type of LPP-HMGA2 transcript in four cases.
BACKGROUND
In a subset of lipoma, a specific t(3;12)(q27-28;q14-15) chromosomal translocation leads to the fusion of the high mobility group A2 (HMGA2) gene and the lipoma preferred partner (LPP) gene. Although the expression of HMGA2-LPP fusion gene has been reported in lipomas, the reciprocal LPP-HMGA2 fusion gene has rarely been described.


METHODS
Ninety-eight cases of lipoma were analyzed for the possible expression of HMGA2-LPP and LPP-HMGA2 fusion genes using a reverse-transcription polymerase chain reaction method.


RESULTS
Ten lipomas (10%) revealed both HMGA2-LPP and LPP-HMGA2 fusion transcripts, nine (9%) only HMGA2-LPP, and three (3%) only LPP-HMGA2. DNA sequencing analysis demonstrated that the HMGA2-LPP transcript in 19 lipomas consisted of exons 1-3 of HMGA2 and exons 9-11 of LPP, which was described previously. Out of 13 lipomas with LPP-HMGA2 transcript, 9 were associated with a previously reported LPP-HMGA2 fusion transcript, which fuses exon 8 of LPP to exon 4 of HMGA2, while 4 with a novel type of LPP-HMGA2 fusion transcript, which fuses exon 7 of LPP to exon 4 of HMGA2.


CONCLUSIONS
In addition to the HMGA2-LPP fusion gene, the LPP-HMGA2 fusion gene could have some specific roles for lipomagenesis. The biological implications of the expression and the variation of LPP-HMGA2 fusion transcripts need to be elucidated.
Kubo
Takahiro
T
Department of Orthopaedic Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
Matsui
Yoshito
Y
Naka
Norifumi
N
Araki
Nobuhito
N
Goto
Tomohiro
T
Yukata
Kiminori
K
Endo
Kenji
K
Yasui
Natsuo
N
Myoui
Akira
A
Kawabata
Hidehiko
H
Yoshikawa
Hideki
H
Ueda
Takafumi
T
D000328:Adult; D000368:Aged; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D025743:HMGA2 Protein / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D060588:LIM Domain Proteins; D008067:Lipoma / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000378:metabolism; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
D003598:Cytoskeletal Proteins; D025743:HMGA2 Protein; D060588:LIM Domain Proteins; C103594:LPP protein, human; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins