RESUMO
The HMGA2 gene has been found to be rearranged in a variety of benign solid tumors. However, in all tumor entities where aberrations of the corresponding chromosomal region have been found, a large percentage of tumors do not show any detectable cytogenetic deviation. Thus, the question arises whether or not in some of these cases, small subpopulations of tumor cells characterized by HMGA2 rearrangements exist. The existence of these populations would strongly suggest a secondary nature of the chromosomal aberrations. Herein, we have addressed this question by RT-PCR analyses of the HMGA2-LPP fusion resulting from t(3;12)(q27 approximately q28;q14 approximately q15) in a series of 61 pulmonary chondroid hamartomas (PCH) with an apparently normal karyotype. As a result, the HMGA2-LPP fusion transcript was amplified in only one of 61 PCH with a normal karyotype. In this case, fluorescence in situ hybridization analysis revealed a hidden chromosomal aberration. The absence of the HMGA2-LPP fusion in small populations of tumors with a normal karyotype suggests the primary nature of chromosomal rearrangements in the development of PCH affected by those aberrations.
Assuntos
Proteínas do Citoesqueleto/genética , Proteína HMGA2/genética , Hamartoma/genética , Neoplasias Pulmonares/genética , Proteínas de Fusão Oncogênica/genética , Translocação Genética/genética , Cromossomos Humanos Par 12/genética , Cromossomos Humanos Par 3/genética , Hamartoma/patologia , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Proteínas com Domínio LIM , Neoplasias Pulmonares/patologia , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
In a variety of benign solid human tumors the high mobility group protein gene HMGIC is affected by aberrations involving the chromosomal region 12q14 through q15. Beside the two predominant alterations t(3;12) (q27 through 28;q14 through q15) and t(12;14)(q14 through q15;q23 through q24), the t(12;13)(q14 through q15;q12 through q14) is another aberration observed recurrently in these tumors. Very recently, an HMGIC-LHFP (lipoma HMGIC fusion partner) fusion gene has been detected in a lipoma with a t(12;13). The results of the present study demonstrated the absence of the HMGIC-LHFP fusion in three pulmonary chondroid hamartomas (PCH) with complex aberrations involving chromosomal regions 12q13 through q15 and 13q12q through q14 and one PCH with a simple t(12;13)(q14 through 15;q13) by reverse transcription-polymerase chain reaction. Thus, intragenic rearrangements within the LHFP gene leading to its fusion to HMGIC are not a consistent finding in mesenchymal tumors with clonal aberrations of both chromosomal regions 12q13 through q15 and 13q12 through q14.