Surface immunoglobulin positive lymphoblastic leukemia in adults; a genetic spectrum

B Lymphoblastic Leukemia/Lymphoma With Burkitt-like Morphology and IGH/MYC Rearrangement: Report of 3 Cases in Adult Patients

Isolated MYC rearrangement without other recurrent genetic abnormalities is rare in B lymphoblastic leukemia/lymphoma (B-ALL/LBL), with most cases reported in pediatric patients. We report 3 adult cases with lymphoblasts showing a precursor B cell immunophenotype, and isolated MYC/IGH translocation. All 3 cases occurred in male patients with initial presentation of diffuse lymphadenopathy. Cases 1 and 2 had B-ALL with significantly increased lymphoblasts in peripheral blood and bone marrow. Case 3, a patient with human immunodeficiency virus infection, had the diagnosis of B-LBL made on a retroperitoneal lymph node biopsy and had no peripheral blood or bone marrow involvement. The leukemic and lymphoma cells in all 3 cases demonstrated Burkitt lymphoma-like morphology with deeply basophilic cytoplasm and numerous cytoplasmic vacuoles. However, all 3 had immature immunophenotypes including expression of terminal deoxynucleotidyl transferase (TdT), absence of BCL6, and dim-to-negative CD45. CD20 was largely negative in 2 of 3 cases. All 3 had confirmed MYC/IGH translocation, but lacked rearrangements of BCL2 or BCL6. EBV was negative by Epstein-Barr virus encoded small RNA in situ hybridization. Treatment protocols varied, including both high-risk ALL-type (protocol 8707) and high-grade lymphoma regimens (hyper-CVAD [cyclophosphamide, vincristine, adriamycin, and dexamethasone]), but no patient achieved continuous complete remission. These cases seem to represent a distinct biological phenomenon, in which a MYC translocation may be acquired at an immature stage of differentiation, thus manifesting features of both B-ALL/LBL and Burkitt lymphoma.

A Graphene Oxide-Based Fluorescent Aptasensor for the Turn-on Detection of CCRF-CEM

A convenient, low-cost, and highly sensitive fluorescent aptasensor for detection of leukemia has been developed based on graphene oxide-aptamer complex (GO-apt). Graphene oxide (GO) can absorb carboxyfluorescein-labeled Sgc8 aptamer (FAM-apt) by π-π stacking and quench the fluorescence through fluorescence resonance energy transfer (FRET). In the absence of Sgc8 target cell CCRF-CEM, the fluorescence is almost all quenched. Conversely, when the CCRF-CEM cells are added, the quenched fluorescence can be recovered rapidly and significantly. Therefore, based on the change of fluorescence signals, we can detect the number of CCRF-CEM cells in a wide range from 1 × 102 to 1 × 107 cells/mL with a limit of detection (LOD) of 10 cells/mL. Therefore, this strategy of graphene oxide-based fluorescent aptasensor may be promising for the detection of cancer.

Illegitimate RAG-mediated recombination events are involved in IKZF1 Δ3-6 deletion in BCR-ABL1 lymphoblastic leukaemia

Breakpoint cluster region-Abelson murine leukaemia viral oncogene homologue 1 (BCR-ABL1), encoded by the Philadelphia (Ph) chromosome, is the characteristic of chronic myeloid leukaemia (CML) and a subset of acute lymphoblastic leukaemia (ALL). We demonstrated that expression of the Ik6 transcript, which lacked exons 3-6, was observed exclusively in BCR-ABL1(+) B ALL and lymphoid blast crisis CML (BC-CML) patients harbouring the IKZF1 Δ3-6 deletion. To confirm the hypothesis that illegitimate recombination activating gene protein (RAG)-mediated recombination events are involved in IKZF1 Δ3-6 deletion in BCR-ABL1 lymphoblastic leukaemia, we first demonstrated that the expression rates of RAG1 and RAG2, collectively called RAG, were higher in ALL and BC-CML (lymphoid). Notably, analysis of relationships among RAG, BCR-ABL1 and Ikaros 6 (Ik6) showed that Ik6 can be generated only if RAG and BCR-ABL1 are co-existing. The sequencing data showed that the deleted segments of introns 2 and 6 contained cryptic recombination signal sequences (cRSSs) and frequently had non-template nucleotides inserted between breakpoints. Furthermore, we used chromatin immunoprecipitation (ChIP) technology and demonstrated that the sequences directly flanking IKZF1 Δ3-6 deletion breakpoints have significantly higher levels of histone H3 lysine 4 trimethylation (H3K4me3) modifications. Overall, RAG expression, good-quality cRSS and a specific chromatin modification, H3K4me3, satisfy the conditions of RAG's off-target effects on IKZF1. Our work provides evidence for RAG-mediated IKZF1 Δ3-6 deletion. Our results raise the prospect that RAG is a valuable biomarker in disease surveillance. Dissecting the contribution of RAG should not only provide valuable mechanistic insights, but will also lead to a new therapeutic direction.

B Lymphoblastic Leukemia With a Novel t(11;15) (q23;q15) and Unique Burkittoid Morphologic and Immunophenotypic Findings in a 9-Year-Old Boy

B lymphoblastic leukemia is a B progenitor cell neoplasm with a range of immature immunophenotypes and several associated cytogenetic lesions. In contrast, Burkitt leukemia/lymphoma is a mature B lymphocyte neoplasm with a characteristic germinal center immunophenotype and MYC rearrangement. With modern immunophenotyping and cytogenetic methods, the distinction between these 2 entities is seldom ambiguous. Herein, we report a case of a 9-year-old white boy with circulating leukemic cells that demonstrate morphologic overlap between Burkitt leukemia and B lymphoblastic leukemia. Flow cytometry and immunohistochemical stains demonstrated expression of sets of markers with overlap between immature and mature immunophenotypes. While the leukemic cells tested positive for terminal deoxynucleotidyl transferase (TdT), they expressed CD20, BCL6 (in a subset), and lambda-restricted surface light chain. Molecular studies confirmed a true clonal light chain rearrangement, whereas fluorescent in situ hybridization (FISH) results were negative for MYC rearrangement. Metaphase cytogenetics identified a novel gene rearrangement, t(11;15)(q23;q15), that does not involve the MLL gene. This unique cytogenetic abnormality involves the loss of INO80, an adenosine triphosphatase (ATPase) with DNA binding ability. This cytogenetic abnormality may represent a unique feature of this overlap entity of B lymphoblastic lymphoma that expresses markers of maturity and demonstrates Burkitt-like morphology.

Highly sensitive detection of leukemia cells based on aptamer and quantum dots

Detection of leukemia at the early stage with high sensitivity is a significant clinical challenge for clinicians. In the present study, we developed a sensitive detector consisting of the product of oligonucleotides hybridized with semiconductor quantum dots (QDs) to generate a stronger fluorescent signal so that leukemic cells can be captured. In the present study, a biotin-modified Sgc8 aptamer was used to identify CCRF-CEM cells, and then biotin-appended QDs were labeled with the aptamer via streptavidin and biotin amplification interactions. We described the complex as QDs-bsb-apt. CEM and Ramos cells were used to assess the specificity and sensitivity of the novel complex. These results revealed that the complex could be more effective in diagnosing leukemia at the early stage. In conclusion, an innovative structure based on aptamer and QDs for leukemia diagnosis was provided. It has the potential to image tumor cells in vitro or in vivo and to realize the early diagnosis of disease. Furthermore, it may be used to provide guidance for clinicians to implement individualized patient therapy.

Precursor B-Cell Acute Lymphoblastic Leukemia/Lymphoma with L3 Morphology, Philadelphia Chromosome, MYC Gene Translocation, and Coexpression of TdT and Surface Light Chains: A Case Report

Acute lymphoblastic leukemia is predominantly found in children. It is a neoplasm of precursor cells or lymphoblasts committed to either a B- or T-cell lineage. The immature cells in B-acute lymphoblastic leukemia/lymphoma can be small or medium sized with scant or moderate cytoplasm and typically express B-cell markers such as CD19, cytoplasmic CD79a, and TdT without surface light chains. These markers, along with cytogenetic studies, are vital to the diagnosis, classification, and treatment of these neoplasms. We present an unusual case of a precursor B-cell ALL, in an 82-year-old woman, who presented with pancytopenia and widespread lymphadenopathy. The cells show L3 morphology (Burkitt-like lymphoma) with coexpression of TdT and surface light chains in addition to an MYC gene translocation and Philadelphia chromosome.