OBJECTIVETo characterize the profile of chromosomal imbalances of rhabdomyosarcoma(RMS).

METHODSComparative genomic hybridization (CGH) was used to investigate genomic imbalances in 25 cases of primary RMS including 10 cases of alveolar rhabdomyosarcoma (ARM), 12 cases of embryonic rhabdomyosarcoma (ERMS), 3 cases of polymorphic rhabdomyosarcoma (PRMS) and 2 RMS cell lines (A240 originated from ARMS and RD from PRMS), with correlation to histological type, pathologic grading, clinical staging, gender and age, respectively.

RESULTSAll twenty-five rhabdomyosarcomas showed evidence of increased or decreased DNA sequence copy numbers involving one or more regions of the genome. (1) The frequently gained chromosome regions in RMS were 2p, 12q, 6p, 9q, 10q, 1p, 2q, 6q, 8q, 15q, 18q, and the frequently lost chromosome regions were 3p, 11p, 6p. (2) The frequently gained chromosome arms in ARMS were 12q, 2p, 6, 2q, 4q, 10q, 15q. The frequently lost chromosome arms were 3p, 6p, 1q, 5q. The frequently gained chromosome regions in ERMS were 7p, 9q, 2p, 18q, 1p, 8q. The frequently lost chromosome arms in ERMS were 11p. (3) The frequently gained chromosome arms in translocation associated RMS were 12q, 2, 6, 10q, 4q and 15q (> 30%), 3p, 6p, 5q (> 30%) were the frequently loss chromosome arms. The frequently gained chromosome regions in non-translocation associated RMS were 2p, 9q, 18q (> 30%), and 11p, 14q (> 30%) were the frequently loss chromosome regions. Gain of 12q was significantly correlated with the translocation-associated tumors (P < 0.05). (4) Gains of 9q was significantly correlated with clinical staging (P < 0.05).

CONCLUSIONSGain of 2p, 12q, 6p, 9q, 10q, 1p, 2q, 6q, 8q, 15q, 18q and loss of 3p, 11p, 6p may be involved in the tumorigenesis of RMS. Gains of 12q may be correlated with gene fusion/chromosomal translocation in ARMS. Gains of 9q may be correlated with an early tumor stage of RMS.