Frequency of L1721W Polymorphism in TET2 Gene Among a Cohort of Sudanese Patients with Myeloproliferative Disorders: Possible Roles in Pathogenicity and Leukemic Transformation

Abstract

Transformation of myeloproliferative disorders (MPDs) to acute leukemia is an evitable event that represents a stumbling block in the management of patients. The Janus Kinase-2 JAK2V617F mutation of MDP does not clarify the phenotypic variability observed in this disorder. But, a mutations in Ten-eleven-translocation-2 (TET2), a putative tumor suppressor gene, was recently implicated in MPDs and other hematologic malignancies. TET-2 is believed to play a role in leukemic transformation. This study aimed to determine the frequency of L1721W polymorphism in TET2 gene in a cohort of Sudanese patients with MPDs. Following informed consent, 25 (25/50, 50%) patients with polycythemia rubra vera (PRV), thirteen patients (13/50, 26%) with essential thrombocythemia (ET), eleven patients (11/50, 22%) with chronic myeloid leukemia (CML), and one patient (1/50, 2%) with primary myelofibrosis (PMF) were enrolled. None of the patients was in the transformation phase. Patients were diagnosed based on clinical picture, hematological parameters and JAK2V617F and BCR_ABL molecular aberrations. JAK2V617F was detected in Ph-negative-MPDs cases as (24/25, 96%) in PRV, (10/13, 76%) in ET, and (1/1, 100%) in PMF. BCR_ABL fusion was detected in all (11/11, 100%) cases of CML. DNA was extracted using the guanidine chloride method, followed by (PCR-RFLP) analysis. Only one patient showed the presence of L1721W polymorphism of the TET2. It was inferred that the low frequency of this transformation within the study cohort [all in chronic phase] probably indicates that it plays a minor role in MPD pathogenesis, while its role in blast transformation needs further studies in MPD patients.