RESUMO
Abstract Introduction: A key step of cancer development is the progressive accumulation of genomic changes resulting in disruption of several biological mechanisms. Carcinoma ex-pleomorphic adenoma (CXPA) is an aggressive neoplasm that arises from a pleomorphic adenoma. CXPA derived from a recurrent PA (RPA) has been rarely reported, and the genomic changes associated with these tumors have not yet been studied. Objective: We analyzed CXPA from RPAs and RPAs without malignant transformation using array-comparative genomic hybridization (array-CGH) to identify somatic copy number alterations and affected genes. Methods: DNA samples extracted from FFPE tumors were submitted to array-CGH investigation, and data was analyzed by Nexus Copy Number Discovery Edition v.7. Results: No somatic copy number alterations were found in RPAs without malignant transformation. As for CXPA from RPA, although genomic profiles were unique for each case, we detected some chromosomal regions that appear to be preferentially affected by copy number alterations. The first case of CXPA-RPA (frankly invasive myoepithelial carcinoma) showed copy number alterations affecting 1p36.33p13, 5p and chromosomes 3 and 8. The second case of CXPA-RPA (frankly invasive epithelial-myoepithelial carcinoma) showed several alterations at chromosomes 3, 8, and 16, with two amplifications at 8p12p11.21 and 12q14.3q21.2. The third case of CXPA-RPA (minimally invasive epithelial-myoepithelial carcinoma) exhibited amplifications at 12q13.3q14.1, 12q14.3, and 12q15. Conclusion: The occurrence of gains at chromosomes 3 and 8 and genomic amplifications at 8p and 12q, mainly those encompassing the HMGA2, MDM2, WIF1, WHSC1L1, LIRG3, CDK4 in CXAP from RPA can be a significant promotional factor in malignant transformation.
Resumo Introdução: Uma etapa fundamental do desenvolvimento do câncer é o acúmulo progressivo de alterações genômicas, resultando na ruptura de vários mecanismos biológicos. Carcinoma ex-adenoma pleomórfico (CXAP) é uma neoplasia agressiva que surge a partir de um adenoma pleomórfico. O CXAP derivado de um AP recorrente (APR) foi raramente relatado e, até o momento, as alterações genômicas associadas a esses tumores não foram estudados. Objetivo: Avaliar as diferenças entre os CXAPs decorrentes de APRs e os APRs sem transformações malignas usando hibridização genômica comparativa em microarrays (array Comparative Genomic Hibridization - aCGH) a fim de identificar alterações no número de cópias somáticas e os genes afetados. Método: Amostras de DNA extraídas de tumores provenientes de tecido emblocado em parafina foram submetidos à investigação com a técnica aCGH, e os dados foram analisados com o Nexus Copy Number Discovery Edition v.7. Resultados: Não observamos alterações no numero de cópias somáticas nos APRs sem transformação maligna. Quanto ao CXAP de APR, embora os perfis genômicos sejam exclusivos para cada caso, detectamos algumas regiões cromossômicas que pareciam ser preferencialmente afetadas por alterações no número de cópias. O primeiro caso de CXAP-APR (carcinoma mioepitelial francamente invasivo) apresentou alterações no numero de cópias afetando 1p36.33p13, 5p e cromossomos 3 e 8. O segundo caso de CXAP-APR (carcinoma epitelialmioepitelial francamente invasivo) apresentou várias alterações nos cromossomos 3, 8 e 16, com duas amplificações em 8p12p11.21 e 12q14.3q21.2. O terceiro caso de CXAP-APR (carcinoma epitelial-mioepitelial minimamente invasivo) apresentou amplificações em 12q13.3q14.1, 12q14.3, e 12q15. Conclusão: A ocorrência de ganhos de cromossomos 3 e 8, e as amplificações genômicas em 8p e 12q, principalmente aquelas que englobam os HMGA2, MDM2, WIF1, WHSC1L1, RG3, CDK4 no CXAP decorrente de APR podem ser fatores promocionais significativos para a transformação maligna.
Assuntos
Humanos , Masculino , Feminino , Adulto , Idoso , Neoplasias das Glândulas Salivares/genética , Transformação Celular Neoplásica/genética , Adenoma Pleomorfo/genética , Neoplasias das Glândulas Salivares/patologia , Transformação Celular Neoplásica/patologia , Adenoma Pleomorfo/patologia , Recidiva Local de NeoplasiaRESUMO
INTRODUCTION: A key step of cancer development is the progressive accumulation of genomic changes resulting in disruption of several biological mechanisms. Carcinoma ex-pleomorphic adenoma (CXPA) is an aggressive neoplasm that arises from a pleomorphic adenoma. CXPA derived from a recurrent PA (RPA) has been rarely reported, and the genomic changes associated with these tumors have not yet been studied. OBJECTIVE: We analyzed CXPA from RPAs and RPAs without malignant transformation using array-comparative genomic hybridization (array-CGH) to identify somatic copy number alterations and affected genes. METHODS: DNA samples extracted from FFPE tumors were submitted to array-CGH investigation, and data was analyzed by Nexus Copy Number Discovery Edition v.7. RESULTS: No somatic copy number alterations were found in RPAs without malignant transformation. As for CXPA from RPA, although genomic profiles were unique for each case, we detected some chromosomal regions that appear to be preferentially affected by copy number alterations. The first case of CXPA-RPA (frankly invasive myoepithelial carcinoma) showed copy number alterations affecting 1p36.33p13, 5p and chromosomes 3 and 8. The second case of CXPA-RPA (frankly invasive epithelial-myoepithelial carcinoma) showed several alterations at chromosomes 3, 8, and 16, with two amplifications at 8p12p11.21 and 12q14.3q21.2. The third case of CXPA-RPA (minimally invasive epithelial-myoepithelial carcinoma) exhibited amplifications at 12q13.3q14.1, 12q14.3, and 12q15. CONCLUSION: The occurrence of gains at chromosomes 3 and 8 and genomic amplifications at 8p and 12q, mainly those encompassing the HMGA2, MDM2, WIF1, WHSC1L1, LIRG3, CDK4 in CXAP from RPA can be a significant promotional factor in malignant transformation.