T-stem cell leukemia/lymphoma with both myeloid lineage conversion and T-specific δ recombination

CD56+ CD7+ Stem Cell Leukemia/Lymphoma with D2-J.DELTA.1 Rearrangement.

“…All patients' blasts had incomplete D52J81rearrangementat least on one allele even in the absence of CyCD3e(2/2). This D2-J81 recombination, which is promoted by T-cell specific enhancer (18), appears to be T-lineage specific (14)(15)(16)(17)(18)(19). Blasts in patient 3 showed IgH rearrangement as B lineage marker.…”

“…It has been suggested that D2-J8 occurs at the earliest stage of T-cell differentiation (prothymocyte stage I ) followed later by expression of cytoplasmic CD3e (CyCD3e) ( 14). Analysis of D2-J8 in the TCRSlocus should further clarify the lineage and clonality of leukemic cells even at the stem cell stage ofT-cell differentiation (14,17,19,20). In this report, we describe the clinical, morphologic, immunologic, karyotypic, and genotypic features of three CD56+…”

“…In patient 3, the rearrangements of IgH and TCR(3 genes were noticed, while all exhibited a common4.8 kb Hind III rearranged band upon J8l probe analysis. This indicated an incomplete D2-J81 recombination (14)(15)(16)(17)(18)(19) (Figs. 3 and 4).…”

T Cell Receptor δ-Chain Gene Rearrangement in a Novel Case of Adult NK Cell Leukemia

“…Rearrangement of TCR δ-chain gene has been previously reported in several cases of leukemia and lymphoma of non-T-cell origin [6, 7]and in a few cases of NK/myeloid leukemia [8], but its significance remained debated. Molecular analyses of TCR genes have shown that α-, β- and γ-genes rearrange early during T cell development and support T lineage commitment [9, 10], whereas TCR δ-gene rearrangement did not provide firm conclusions as to lineage derivation.…”

“…Cases of myeloid/NK cell acute leukemia have also been identified [14]and they were all characterized by both a myeloid/NK cell precursor phenotype (CD56+, CD7+, CD34+, CD33+), a morphological lymphoblastoid appearance with lack of azurophilic granules and no clonal rearrangement of the TCR β- and γ-chain gene. Malignancies described as CD56+/CD7+ stem cell leukemia/lymphoma, most with D2-Jδ1 gene rearrangement [15], were also reported [8, 16, 17]. …”