Assuntos
Leucemia Megacarioblástica Aguda/genética , Proteínas de Fusão Oncogênica/genética , Proteínas/genética , Proteínas Proto-Oncogênicas c-ets/genética , Proteínas Repressoras/genética , Translocação Genética , Proteínas de Ciclo Celular , Pré-Escolar , Cromossomos Humanos Par 12 , Cromossomos Humanos Par 5 , Feminino , Humanos , Variante 6 da Proteína do Fator de Translocação ETSRESUMO
Retinoblastoma (RB) is a malignant childhood tumor that results from loss or inactivation of both alleles of the RB1 gene. Human papillomavirus (HPV) DNA sequences have been found in RB tissue, suggesting a role of the viral infection with RB. We here describe a child with disseminated bilateral RB without familial history, who displayed a loss of material from 10p. Fluorescence in situ hybridization studies showed a somatic loss of both alleles of the RB1 gene. Moreover, sequences for HPV-6a were detected on DNA extracted from eye tumor tissue and from nonstimulated peripheral blood leukocyte cultures. The eye tumor tissue was also positive for HPV L1 viral proteins. Repeated loss of the short arm of chromosome 10 in HPV-transfected keratinocytes has been reported. Loss of heterozygosity in 10p14 approximately p15 is also frequent in cervical cancers. Therefore, it seems probable that the abnormalities on 10p detected in the present case are related to the HPV infection. Thus, HPV could be a cofactor in the progression of RB by promoting nonrandom additional mutations.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 10 , Neoplasias Oculares/genética , Papillomaviridae/isolamento & purificação , Retinoblastoma/genética , DNA Viral/análise , Neoplasias Oculares/virologia , Feminino , Humanos , Lactente , Neoplasias Primárias Múltiplas , Reação em Cadeia da Polimerase , Retinoblastoma/virologiaRESUMO
The t(9;22) is present in almost all cases with chronic myelocytic leukemia (CML). Around 5% of these patients show complex translocations involving a third chromosome in addition to chromosomes 9 and 22. All chromosomes have participated in these variants and the BCR-ABL1 hybrid gene is always present. We describe a CML case with a new complex t(9;22;16)(q34;q11.2;p13). Seven months after imatinib treatment a karyotype showed the appearance of a clone with a standard t(9;22) in addition to the clone with the complex translocation. The b3a2 transcript of BCR-ABL1 was detected both at diagnosis and 7 months after therapy. In CML, both complex translocations and standard translocations have the same prognosis. However, these complex variants could contribute to the tumoral evolution by conferring selective advantages that, in turn, cause the preferential manifestation at diagnosis of clones with complex translocations.
