Estudio de las aneuploidías del cromosoma 17 y la deleción del gen TP53 en neoplasias hematológicas, por la técnica del FISH-bicolor

Abstract

RESUMEN: Las neoplasias hematológicas se caracterizan por presentar una amplia diversidad de alteraciones genéticas. Se analizaron 15 muestras de diferentes tipos de neoplasias hematológicas mediante el FISH, para detectar aneuplodías del cromosoma17 y la deleción del gen TP53. En 11 de las 15 muestras se realizaron análisis cromosómicos por citogenética convencional; 6 de las 11 muestras tenían cariotipo anormal (54.5%), se detectaron 3 translocaciones y 3 mosaicismos. Análisis de FISH en 15 muestras mostró un 26.7% de aneuplodía del cromosoma 17 y un 33.3% con deleción del gen TP53. De los 6 casos con cariotipo anormal, 2 tenían alteraciones por FISH. En 5 casos se detectaron alteraciones cromosómicas por FISH, las cuales no se observaron por citogenética convencional. Solo 3 (20%) de las 15 muestras analizadas fueron normales para el análisis cromosómico por citogenética convencional y FISH. En este trabajo se corrobora que la aneuplodía del cromosoma 17 y la deleción del gen TP53 tienen una baja incidencia en las neoplasias hematológicas. Si embargo, el valor pronóstico de estas alteraciones genéticas no esta bien definido.

ABSTRACT: Hematological neoplasias are characterized by a wide spectrum of genetic alterations. We analyzed 15 specimens from patients with various types of hematological malignancies by means of the FISH technique in order to detect aneuploidy of chromosome 17 and deletion of TP53 gene. In 11 of them chromosomal analyses were also carried out using conventional cytogenetic techniques; in 6 of these 11 specimens (54.5%) abnormal karyotypes were detected, namely: 3 translocations and 3 mosaicisms. FISH results revealed that in 26.7% of the 15 specimens there was chromosome 17 aneuploidy, and that 33.3% had TP53 deletion. Out of the 6 cases with abnormal karyotypes, further alterations were detected in two by FISH. In 5 cases chromosomal abnormalities were detected by FISH but not by the conventional cytogenetic procedures. Only in 3 (20%) out of the 15 specimens the results of chromosomal analyses were normal by both the conventional cytogenetics and FISH. These results corroborate the low frequency of chromosome 17 aneuploidy and of TP53 gene deletion in hematological neoplasias. However, the prognostic value of these genetic alterations is still not well defined.