Concomitant rearrangements of T-cell beta- and gamma-chain genes in childhood T-lineage leukemia/lymphoma.

Similar to the immunoglobulin (Ig) gene rearrangements in B-lineage cells, identification of T-cell receptor (TCR) gene rearrangements is a novel clonal marker and necessary to establish a T-cell lineage. The function of T-cell gamma-chain (T gamma) gene is still unknown, but because of its shared properties with T-cell alpha-chain (T alpha) and T beta genes, we analysed T gamma gene organization in 10 patients with T-lineage leukemia/lymphoma as well as in non-T lineage leukemias. All 10 cases of T-lineage leukemia/lymphoma, whose phenotypes were different, demonstrated T gamma gene rearrangements as well as T beta gene rearrangements. In contrast, among the non-T-lineage leukemias, the emergence of T beta and/or T gamma gene rearrangements was varied. Based on these findings, concomitant rearrangements of T beta and T gamma genes are characteristic in childhood T-lineage leukemia/lymphoma regardless of their phenotypic differences. Furthermore, no obvious developmental hierarchy was observed between T beta and T gamma gene arrangements in these leukemia/lymphoma cells.