Detection of TET2, KRAS and CBL variants by Next Generation Sequencing and analysis of their correlation with JAK2 and FLT3 in childhood AML

Background: Acute myeloid leukemia (AML) is a heterogeneous clonal disorder in terms of cytogenetic and molecular aberrations. Ten-Eleven-Translocation 2 ( TET2 ), Kirsten rat sarcoma viral oncogene homolog ( KRAS ), and Casitas B-cell lymphoma ( CBL ) have an important role pathogenesis of acute myeloid leukemia (AML) and their activated mutations confer proliferative and survival signals. Aim: In this study, we aimed to find possible genetic markers for molecular analysis in childhood AML by screening hot-spot exons of TET2 , KRAS , and CBL using Next Generation Sequencing (NGS) analysis. In addition, association between found variants and mutations of Januse Kinase-2 ( JAK2) and Fms Related Tyrosine Kinase ( FLT3 ) were analyzed which are important prognostic risk factors for AML. Methods: Eight patients who were diagnosed with pediatric AML at Losante Pediatric Hematology–Oncology Hospital were included to the study. Hot-spot exons of TET2 , KRAS and CBL genes were screened using the NGS method. Furthermore, FLT3-Internal Tandem Duplicate ( FLT3-ITD ) and JAK2 -V617F were analyzed by Real Time Polymerase chain Reaction (Real Time-PCR). Results: In total, we identified 20 variants in studied genes by NGS. In our patient group, 16 variants in the TET2 (seven novel, seven missense and two silent), two variants in the KRAS  (one missense and one intronic) and two variants in the CBL (two novel) were found. All of AML patients were found negative for JAK V617 F. Three of the eight patients (37.5%) showed mutations of both FLT3-ITD and TET2 , KRAS , CBL . Conclusion: We found novel mutations for TET2 , KRAS , and CBL . The detected variants in this article seem to be the first screening results of genes studied by NGS in childhood AML patients. Our results also showed some degree of association between FLT3-ITD and TET2 , KRAS , CBL  mutations. Keywords: Childhood acute myeloid leukemia; Mutation; TET2 ; KRAS ; CBL ; Next Generation Sequencing