Dados do Trabalho

Título

Frequency and Clinical Aspects of ETV6-RUNX1 Fusion Gene in Childhood Acute Lymphoblastic Leukemia in Amazonian Population

Introdução

In B-cell acute lymphoblastic leukemia (ALL-B) one of the markers are chromosomal translocations and the most frequent is t (12;21) which results in ETV6-RUNX1 gene fusion. This alteration is diagnosed in approximately 25% of patients with ALL-B. The genetic basis is related to alterations in the lymphoid transcription factors, which can silence key genes and regulatory regions, thus the cells remain in a lymphoid progenitor state and accumulate in the bone marrow giving rise to leukemia

Objetivo

The aim of this study was to evaluate the ETV6-RUNX1 gene fusion frequency in an Amazonian population diagnosed with ALL, and associate these finding with clinical aspects, such as leukocyte and platelet counts, number of blasts, hemoglobin and LDH dosage

Métodos

5mL of peripheral blood was collected and the total RNA was extracted using the TRIzol reagent. High Capacity Reverse Transcription Kit was used to obtain cDNA, wich was submitted to a Nested PCR reaction using pairs of external and internal primers. In the 1st round, 6.25 µL GoTaq Colorless Master Mix 2x and 4.25 µL Nuclease Free H2O were used and 0.5µL of each pair of external primer and 1 µL of cDNA were added. The mixture was placed in the thermal cycler with the program: 35 cycles, divided into: denaturation at 95°C for 30'', annealing at 65°C for 30'', and extension at 72°C for 1'. And for the 2nd PCR, the same reagents of the 1st PCR were used, but with the use of internal primers and the product of the 1st PCR as a sample and the thermocycling conditions were the same as the 1st round. All PCR products were subjected to electrophoresis in 1.5% agarose gel, stained with Sybr Safe and for visualization of the bands, the transilluminator was used. Ethics committee nr. 4.040.805

Resultados

In 58 patients analyzed, 59% male and 41% female, the mean age was 8.13 years ± 4.78 years (ranging from 0-18). ETV6-RUNX1 fusion expression was found in 41.4% of patients. 24.1% expressed others fusion transcripts and 31% did not present any of the investigated fusions. Fisher's exact test showed no association between gene fusions and sex. The analysis of hematological (leukocyte and platelet count, number of blasts and hemoglobin dosage) and biochemical (lactic dehydrogenase - LDH) parameters was performed in relation to the studied groups. ETV6-RUNX1 patients had a mean WBC count, number of blasts and LDH of 41000mm³, 33% and 1017U/L, respectively. The Kruskal Wallis test revealed that there is a statistical difference (p<0.05) between the groups and the parameters of the leukocyte count, number of blasts and LDH, revealing that the fusion has a clinical impact with reduction on these hematological and biochemical aspects of the patient

Conclusões

This study found ETV6-RUNX1 to be the most frequent alteration in amazonian patients, corroborating with the international literature. In addition, the proportion between male and female patients is corroborating the findings of other studies. Finally, it was observed that there is a statistical difference between gene fusions when associated with the patient's clinical data, showing that the type of fusion can influence the prognosis

Palavras-chave

ALL-B, ETV6-RUNX1, Fusion Genes