Expression of HMGIY in Three Uterine Leiomyomata with Complex Rearrangements of Chromosome 6

Uterine leiomyomata (UL) are a major public health problem, yet little is known about their etiology. Genetic factors likely influence UL development and growth; for example, approximately 40% of UL have chromosomal abnormalities detectable by conventional cytogenetic analysis, including t(12;14)(q15;q23∼24), rearrangements involving the short arm of chromosome 6 and interstitial deletions of the long arm of chromosome 7. Two high-mobility group (HMG) protein genes, HMGIC and HMGIY, located at 12q15 and 6p21.3, respectively, are involved in rearrangements in various mesenchymal tumors including UL. In this study, we investigated HMGIY expression in three UL with complex cytogenetic rearrangements of 6p21.3 by reverse transcriptase-polymerase chain reaction (RT-PCR) and electrophoretic shift assay (EMSA). Our findings suggest that there are multiple mechanisms for HMGIY dysregulation, which may include post-translational modification of the hmgiy protein and dysregulation due to different translocation partners. Furthermore, the mechanism dysregulating HMGIY in UL with 6p21.3 and 14q23∼24 rearrangements may be similar to the mechanism dysregulating HMGIC in UL characterized as t(12;14)(q15;q23∼24), because of the common involvement of an HMG gene and a gene at 14q23∼24.