Prognostic Significance ofNOTCH1andFBXW7Mutations in Pediatric T-ALL

The NOTCH signaling pathway plays important role in the development of multicellular organisms, as it regulates cell proliferation, survival, and differentiation. In adults, it is essential for the T- or B-lymphocyte lineage commitment.NOTCH1and FBXW7 mutations both lead the activation of theNOTCH1pathway and are found in the majority of T-ALL patients. In this study, the mutation analysis ofNOTCH1andFBXW7genes was performed in 87 pediatric T-ALLs who were treated on the ALL-BFM protocols. In 19 patients (22%), activatingNOTCH1mutations were observed either in the heterodimerization domain or in the PEST domain and 7 cases (10%) demonstrated FBXW7 mutations (2 cases had bothNOTCH1andFBXW7mutations). We also analyzed the relationship of the mutation data between the clinical and biological data of the patients.NOTCH1andFBXW7,NOTCH1alone were found correlated with lower initial leucocyte counts which was independent from the sex and T- cell immunophenotype. However,NOTCH1andFBXW7mutations were not predictive of outcome in the overall cohort of pediatric T-ALLs.