Chromosome Translocation t(14;21)(q11;q22) Activates Both OLIG1 and OLIG2 in Pediatric T-cell Lymphoblastic Malignancies and May Signify Adverse Prognosis.

Background/Aim: The chromosome translocation t(14:21)(q11;q22) was reported in four pediatric T-cell lymphoblastic leukemias and was shown to activate the OLIG2 gene. Materials and Methods: A pediatric T-cell lymphoblastic lymphoma was investigated using G-banding chromosome analysis, fluorescence in situ hybridization (FISH), and immunocytochemistry. Results: The malignant cells carried a t(14:21)(q11;q22) aberration. The translocation moves the enhancer elements of TRA/TRD from band 14q11 to 21q22, a few thousands kbp downstream of OLIG1 and OLIG2, resulting in the production of both OLIG1 and OLIG2 proteins. Conclusion: The translocation t(14:21)(q11;q22) occurs in some pediatric T-cell lymphoblastic malignancies. Activation of both OLIG1 and OLIG2 by t(14 ;21)(q11;q22) in T-lymphoblasts and the ensuing deregulation of thousands of genes could explain the highly malignant disease and resistance to treatment that has characterized this small group of patients.