Estudio de las aneuploidías del cromosoma 17 y la deleción del gen TP53 en neoplasias hematológicas, por la técnica del FISH-bicolor / Study of chromosome 17 aneuploidy and of TP53 gene deletion in patients with hematological neoplasias by dualcolor fluorescence in situ hybridization (FISH)

RESUMEN

Las neoplasias hematológicas se caracterizan por presentar una amplia diversidad de alteraciones genéticas. Se analizaron 15 muestras de pacientes con diferentes tipos de neoplasias hematológicas mediante la técnica FISH, para detectar aneuploidías del cromosoma 17 y la deleción del gen TP53. En 11 de ellas se hicieron análisis cromosómicos por citogenética convencional; 6 de las 11 tenían cariotipo anormal (54,5%) se detectaron 3 translocaciones y 3 mosaicismos. El análisis de las 15 muestras mediante la técnica FISH mostró un 26,7% de aneuploidía del cromosoma 17 y un 33,3% con deleción del gen TP53. De los 6 casos con cariotipo anormal, en 2 se detectaron alteraciones por FISH. En 5 casos se detectaron con esta técnica alteraciones cromosómicas no observadas por citogenética convencional. Solo en 3 (20%) de las 15 muestras analizadas el análisis cromosómico resultó normal por citogenética convencional y FISH. En este trabajo se corrobora que la aneuploidía del cromosoma 17 y la deleción del gen TP53 tienen una baja frecuencia en las neoplasias hematológicas. Sin embargo, el valor pronóstico de estas alteraciones genéticas no está 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.