Asunto(s)
Proteínas Serina-Treonina Quinasas/genética , Adulto , Aneuploidia , Deleción Cromosómica , Cromosomas Humanos Par 18/genética , Cromosomas Humanos Par 18/fisiología , Cromosomas Humanos Par 2/genética , Cromosomas Humanos Par 2/fisiología , Familia , Femenino , Humanos , Lactante , Isocromosomas/genética , Isocromosomas/fisiología , Cariotipificación , Masculino , Proteínas Serina-Treonina Quinasas/fisiologíaRESUMEN
Testicular germ cell tumors (TGCTs) are the most common solid tumors in young adult men. They constitute a unique pathology because of their embryonic and germ origin and their special behavior. Genetic predisposition, environmental factors involved in their development and genetic aberrations have been under study in many works throughout the last years trying to explain the susceptibility and the transformation mechanism of TGCTs. Despite the high rate of cure in this type of tumors because its particular sensitivity to cisplatin, there are tumors resistant to chemotherapy for which it is needed to find new therapies. In the present work, it has been carried out a literature review on the most important molecular aspects involved in the onset and development of such tumors, as well as a review of the major developments regarding prognostic factors, new prognostic biomarkers and the possibility of new targeted therapies (AU)
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Asunto(s)
Humanos , Masculino , Adulto Joven , Neoplasias de Células Germinales y Embrionarias/diagnóstico , Biología Molecular/métodos , Biología Molecular/normas , Neoplasias Testiculares/diagnóstico , Cisplatino/análisis , Cisplatino/aislamiento & purificación , Pronóstico , Seminoma/diagnóstico , Perfilación de la Expresión Génica/métodos , Perfilación de la Expresión Génica/normas , Pruebas Genéticas/métodos , Predisposición Genética a la Enfermedad/genética , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Isocromosomas/genética , Isocromosomas/fisiologíaRESUMEN
Amplicons--large, nearly identical repeats in direct or inverted orientation--are abundant in the male-specific region of the human Y chromosome (MSY) and provide targets for intrachromosomal non-allelic homologous recombination (NAHR). Thus far, NAHR events resulting in deletions, duplications, inversions, or isodicentric chromosomes have been reported only for amplicon pairs located exclusively on the short arm (Yp) or the long arm (Yq). Here we report our finding of four men with Y chromosomes that evidently formed by intrachromosomal NAHR between inverted repeat pairs comprising one amplicon on Yp and one amplicon on Yq. In two men with spermatogenic failure, sister-chromatid crossing-over resulted in pseudoisoYp chromosome formation and loss of distal Yq. In two men with normal spermatogenesis, intrachromatid crossing-over generated pericentric inversions. These findings highlight the recombinogenic nature of the MSY, as intrachromosomal NAHR occurs for nearly all Y-chromosome amplicon pairs, even those located on opposing chromosome arms.
Asunto(s)
Cromosomas Humanos Y/genética , Recombinación Homóloga , Secuencias Invertidas Repetidas , Intercambio de Cromátides Hermanas , Secuencia de Bases , Centrómero , Aberraciones Cromosómicas , Inversión Cromosómica , Humanos , Hibridación Fluorescente in Situ , Isocromosomas/fisiología , Masculino , Datos de Secuencia Molecular , EspermatogénesisAsunto(s)
Síndrome de Bloom/complicaciones , Cromosomas Humanos Par 5 , Isocromosomas , Síndromes Mielodisplásicos/complicaciones , Adolescente , Síndrome de Bloom/diagnóstico , Síndrome de Bloom/epidemiología , Síndrome de Bloom/genética , Femenino , Humanos , Incidencia , Isocromosomas/fisiología , Síndromes Mielodisplásicos/diagnóstico , Síndromes Mielodisplásicos/epidemiología , Síndromes Mielodisplásicos/genética , Pediatría/estadística & datos numéricosRESUMEN
B chromosomes in Prochilodus lineatus, a migratory neotropical fish, were analyzed in a comparative study among populations from the Dourada lagoon (State of Paraná, Brazil) and from Mogi-Guaçu river (State of São Paulo, Brazil). The data on C-banding and fluorescent in situ hybridization with a satellite DNA probe (SATH1), indicate that the small metacentric B chromosome might correspond to an isochromosome. On the other hand, both populations presented a distinct set of B chromosomes, differentiated either by their number and by the presence of variant B types in the population from Mogi-Guaçu river. The present results indicate that the B chromosomes of P. lineatus should have an ancient origin, and have undergone a differential evolutionary pathway among distinct populations.
Asunto(s)
Pintura Cromosómica , Cromosomas , Cipriniformes/genética , Evolución Molecular , Cariotipificación , Animales , Centrómero , Mapeo Cromosómico , Pintura Cromosómica/métodos , ADN Satélite/análisis , Femenino , Frecuencia de los Genes , Heterocromatina , Hibridación Fluorescente in Situ , Isocromosomas/fisiología , Masculino , Metafase , Región Organizadora del Nucléolo/metabolismo , Ploidias , Tinción con Nitrato de PlataRESUMEN
An immature teratoma arising in the pineal gland in a 27-year-old male was shown to present an isochromosome 12p as evidenced by cytogenetic and fluorescence in situ hybridization analysis. As i(12p) is characteristic of gonadal germ cell tumors, this case indicates that similar genetic pathways may operate in gonadal and intracranial teratomas.
Asunto(s)
Neoplasias Encefálicas/patología , Isocromosomas/fisiología , Glándula Pineal/patología , Teratoma/patología , Adulto , Cromosomas Humanos Par 12/fisiología , Cromosomas Humanos Par 12/ultraestructura , Citogenética , Germinoma/patología , Humanos , Hibridación in Situ , Masculino , Metafase , Glándula Pineal/ultraestructuraRESUMEN
To determine which segments of a chromosome arm are responsible for the initiation of chiasmate pairing in meiosis, a series of novel isochromosomes was developed in hexaploid wheat (Triticum aestivum L.). These isochromosomes are deficient for different terminal segments in the two arms. It is proposed to call them "asymmetrical." Meiotic metaphase I pairing of these asymmetrical isochromosomes was observed in plants with various doses of normal and deficient arms. The two arms of an asymmetrical isochromosome were bound by a chiasma in only two of the 1134 pollen mother cells analyzed. Pairing was between arms of identical length whenever such were available; otherwise, there was no pairing. However, two arms deficient for the same segment paired with a frequency similar to that of normal arms, indicating that the deficient arms retained normal capacity for pairing. Pairing of arms of different length was prevented not by the deficiency itself, but rather, by the heterozygosity for the deficiency. Whether two arms were connected via a centromere in an isochromosome or were present in two different chromosomes had no effect on pairing. This demonstrates that in the absence of homology in the distal regions of chromosome arms, even if relatively short, very long homologous segments may remain unrecognized in meiosis and will not be involved in chiasmate pairing.