TET2 Promoter DNA Methylation and Expression Analysis in Pediatric B-Cell Acute Lymphoblastic Leukemia

Ewa Musialik,Mateusz Bujko,Michał Matysiak,Agnieszka Wypych,Janusz Siedlecki

doi:10.4081/hr.2014.5333

Abstract

TET2 is a novel tumor suppressor gene involved in several hematological malignancies of myeloid and lymphoid origin. Besides loss-of-function mutations and deletions, hypermethylation of the CpG island at the TET2 promoter was found in human cancer. Previous analysis revealed no TET2 mutations in acute lymphoblastic leukemia (ALL). Since the TET2 promoter methylation status in pediatric ALL has not been reported, the aim of the present study was to determine if promoter hypermethylation may be a mechanism of TET2 inactivation in a group of pediatric ALL cases. Methylation of TET2 promoter region in one (1/45) ALL B-common patient was detected by methylation specific polymerase chain reaction (PCR) and subsequently analyzed by bisulfite sequencing. We found no correlation between promoter methylation and gene expression, measured by quantitative reverse transcriptase-PCR, however the level of TET2 expression in ALL group was significantly decreased compared to children’s normal peripheral blood mononuclear cells and isolated B-cells. TET2 promoter hypermethylation seems to have limited clinical relevance in childhood B-cell ALL due to its low frequency.

Highlights

Myeloid malignancy patients with TET2 mutations or deletions in some cases simultaneously develop lymphoid disorders: B-cell lymphoma or T-cell lymphoma.[17]
We evaluated the level of TET2 expression in pediatric acute lymphoblastic leukemia (ALL)
Additional six normal PBMC samples some new important genetic aberrations have in pediatric ALL has not been reported, the aim were used for the isolation of CD19-positive been found in hematological neoplasms of the present study was to determine if pro- cells with CD19 MicroBeads Kit and MACS sepincluding TET2 mutations

Summary

Introduction

Myeloid malignancy patients with TET2 mutations or deletions in some cases simultaneously develop lymphoid disorders: B-cell lymphoma or T-cell lymphoma.[17]. Additional six normal PBMC samples some new important genetic aberrations have in pediatric ALL has not been reported, the aim were used for the isolation of CD19-positive been found in hematological neoplasms of the present study was to determine if pro- cells with CD19 MicroBeads Kit and MACS sepincluding TET2 mutations. All the other ALL as well carried out using TET2 promoter methylation expression was calculated by the 2–ΔCt method, as pediatric control blood samples were and non-methylation specific primer pairs where Ct was defined as a difference between methylation negative.

Results

Conclusion