Translocation (14;18)(q32;q21) in acute lymphoblastic leukemia: a study of 12 cases and review of the literature

Precursor B-Cell Acute Lymphoblastic Leukemia With MYC and BCL2 Rearrangements Presenting as Extensive Extranodal Disease in an Adolescent

Combined rearrangements of MYC and BCL2 are rare in precursor B-cell acute lymphoblastic leukemia (B-ALL). A 14-year-old boy presented with swelling of the knee and face. Imaging revealed diffuse infiltration of lacrimal glands, parotid glands along with the extensive epidural disease. Morphology and immunophenotype of knee joint aspirate were consistent with precursor B-ALL. Fluorescent in situ hybridization identified rearrangements of MYC and BCL2 genes. The disease was refractory to intensive treatment. The patient died of progressive disease. Precursor B-ALL with combined MYC and BCL2 rearrangements is rare, characterized by an aggressive clinical course, and has an inadequate response to standard therapeutic approaches.

Genetic Testing in the Diagnosis and Biology of Acute Leukemia

OBJECTIVES

The 2017 Workshop of the Society for Hematopathology/European Association for Haematopathology examined the role of molecular genetics in the diagnosis and biology of acute leukemia.

METHODS

Acute leukemias were reviewed in two sessions: "Genetic Testing in Diagnosis of Acute Leukemias" (53 cases) and "Genetics Revealing the Biology of Acute Leukemias" (41 cases).

RESULTS

Cases included acute lymphoblastic leukemia, acute myeloid leukemia, and acute leukemia of ambiguous lineage. Many cases demonstrated genetic alterations of known diagnostic, prognostic, and/or therapeutic significance, while others exhibited alterations that illuminated disease biology. The workshop highlighted the complexity of acute leukemia diagnosis and follow-up, while illustrating advantages and pitfalls of molecular genetic testing.

CONCLUSIONS

Our understanding of the molecular genetics of acute leukemias continues to grow rapidly. Awareness of the potential complexity of genetic architecture and environment is critical and emphasizes the importance of integrating clinical information with morphologic, immunophenotypic, and molecular genetic evaluation.

Clinical and genetic characterization of de novo double-hit B cell precursor leukemia/lymphoma

The 2016 revised World Health Organization (WHO) classification of lymphoid neoplasms included the category of high-grade B cell lymphomas (HGBLs) with combined MYC and BCL2 and/or BCL6 rearrangements (double-hit, DH). However, the clinical features of B cell precursor leukemia (BCP-ALL) that harbor DH genetics remain widely unknown. We performed a retrospective analysis of the German Multicenter Study Group for Adult ALL registry and a literature search for de novo DH-BCP-ALLs. We identified 6 patients in the GMALL registry and 11 patients published in the literature between 1983 and June 2018. Patients of all ages (range, 15-86 years) are affected. There is a high incidence of meningeal disease and other extramedullary disease manifestations. Current treatment approaches are mainly ALL-based and are sufficient to induce first complete remissions, but progression-free survival is only 4.0 months (95% CI, 1.5-6.5 months) and all patients succumb to their disease, once relapsed, with a median survival of 5.0 months (95% CI, 3.1-6.9 months), despite intensive salvage and targeted therapy approaches. Of all patients, only two that attained an initial complete remission were alive at data cutoff. In all cases, the BCL2 gene was rearranged to be in proximity to the IGH locus, whereas MYC had various translocation partners juxtaposed. There was no significant survival difference between IG and non-IG translocation partners (HR, 1.03; 95% CI, 0.33-3.2; p = 0.89). In conclusion, de novo DH-BCP-ALL is an aggressive B cell malignancy with deleterious outcome. Physicians have to be aware of this rare disease subset due to the atypical clinical behavior and especially because latest classification systems do not cover this sub-entity.

De novo acute lymphoblastic leukemia-like disease of high grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements: a case report and literature review

Background

B-cell lymphomas harboring the 8q24/MYC plus 18q21/BCL2 translocations are now referred to as high grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (HGBL-MBR). Although HGBL-MBR is frequently found in cases with diffuse large B-cell lymphoma or Burkitt lymphoma-like B-cell lymphoma, acute lymphoblastic leukemia (ALL)-like disease of HGBL-MBR (AL-HGBL-MBR) has been reported incidentally.

Case presentation

A 69-year-old Japanese woman developed remittent fever and increasing systemic bone pain. The bone marrow examination revealed that more than 90% of nuclear cells were blastoid cells, which were positive for CD10, CD19, CD20, and surface IgMκ and negative for terminal deoxynucleotidyl transferase (TdT). Cytogenetic studies confirmed that the patient had de novo AL-HGBL-MBR with the extra copies of MYC and loss of chromosome 17p. She showed resistance to chemoimmunotherapy and died seven months after the diagnosis. The literature review identified further 47 de novo AL-HGBL-MBR cases within the last 32 years. The median age was 61 years (range, 27 − 86); the male/female ratio was 2.0. Thirty-eight cases (79%) presented a clinical picture of ALL at diagnosis; 14 (36%) of 39 available cases showed central nervous system involvement. Loss of 17p and translocations at 2p12–13, 3q27, 9p13 were frequently observed as additional cytogenetic abnormalities. Although the median survival of 46 available cases was only five months (range, 0.1–18), rituximab use significantly improved the survival of AL-HGBL-MBR (log-rank test, P = 0.0294).

Conclusion

Our patient and most reported de novo AL-HGBL-MBR cases showed resistance to conventional chemoimmunotherapy and disastrous consequences. AL-HGBL-MBL is a rare, but should be considered a distinct clinical condition in HGBL-MBR. Other therapeutic strategies, such as using inhibitors of MYC and BCL2, are needed to overcome the chemoresistance of AL-HGBL-MBR.

De Novo Precursor B-Lymphoblastic Leukemia/Lymphoma With Double-Hit Gene Rearrangements (MYC/BCL-2) Presented With Spinal Cord Compression and Acquired Factor XIII Deficiency

Double-hit lymphomas (DHLs) are aggressive mature B-cell neoplasms associated with rearrangements involving MYC and B-cell lymphoma-2 (BCL-2). Such DH events are extremely rare in B-cell precursor acute lymphoblastic leukemia (B-ALL), especially in young adults. A 29-year-old male patient initially presented to emergency department with right mandibular mass of 2 months duration associated with intermittent fever. Laboratory workup revealed very high lactate dehydrogenase at 2,026.0 U/L. Peripheral blood revealed pancytopenia with many circulating blasts (about 77%). Bone marrow (BM) aspirate revealed infiltration with many small sized blasts of very high nucleocytoplasmic ratio, finely dispersed nuclear chromatin and prominent nucleoli. The BM biopsy reflected marked hypercellularity with diffuse replacement by sheets of blasts, positive for TdT, PAX-5, CD10, cMYC, BCL-2 and CD20 with Ki-67 > 90%. Flow cytometry on BM revealed a precursor B-immunophenotype (CD45 (dim), CD19, CD10, Tdt and CD20). The blasts are negative for cytoplasmic and surface IgM. Cytogenetics revealed complex karyotype: 46,XY,del(6)(q21q23),t(8;22)(q24.1;q11.2),t(14;18)(q32;q21)(20). A diagnosis of B-lymphoblastic leukemia/lymphoma with t(8;22)(q24.1;q11.2) and t(14;18)(q32;q21) was made. Fluorescent in situ hybridization (FISH) analysis revealed an abnormal hybridization signal pattern for CDKN2A probe, indicating biallelic (homozygous) deletion of the short arm of chromosome 9 (9p) in 94% of the cells analyzed. The patient had severe life-threatening bleeding despite of normal prothrombin time (PT) and activated partial thromboplastin time (APTT) due to acquired factor XIII deficiency, an overlooked rare coagulopathy disorder. In addition, the patient developed acute sudden onset paraplegia, and magnetic resonance imaging (MRI) of spine showed acute cord compression which necessitated emergency radiotherapy after which chemotherapy was started on hyper-CVAD (hyperfractionated cyclophosphamide, vincristine, adriamycin, and dexamethasone) protocol. MRI showed dramatic resolution of the mass. Very few cases of B-ALL with DH rearrangement with true precursor B-cell phenotype (positivity for TdT with negativity for surface light chain) have been reported. Many of these had frequent central nervous system (CNS) involvement, with complex karyotypes, highly aggressive course, with short survival of less than 1 year. This case however showed very good response to treatment. In contrary to DHL, de novo B-ALL with double-hit rearrangements is more prevalent in pediatrics and young adults. Although most of reported cases represent transformation of follicular lymphoma, our patient’s young age, acute onset and absent lymphadenopathies all support de novo ALL.

The t(8;14)(q24.1;q32) and its variant translocations: A study of 34 cases

BACKGROUND

The t(8;14)(q24.1;q32) and its variants - the t(2;8)(p12;q24.1) and t(8;22)(q24.1;q11.2) are associated with B-cell neoplasia and result in MYC/immunoglobulin (IG) gene rearrangement.

PATIENTS AND METHODS

We correlated the cytogenetic, molecular and clinico-pathological findings of patients with 8q24 translocations seen in the Department of Haematology, Christian Medical College, Vellore, from January 2003 to December 2015.

RESULTS

There were 34 patients with 8q24 translocations (31, ALL and three myeloma). The t(8;14) was seen in 25 patients, t(8;22) in seven and t(2;8) in two. The salient findings were as follows: 85% males; 79% adults, median age 37 years; L3 morphology in 61%; mature B immunophenotype in 77%; extra-medullary disease in 41%; additional abnormalities in 28 (85%), notably, structural abnormalities of chromosome 1q (41%) and 13q (9%) and monosomy 13 (15%); complex karyotypes in 68%. There were two double-hit lymphoma/leukemia, one with a t(14;18)(q32;q21) and the other with a t(3;14)(q27;q11.2), associated with nodal high grade B cell lymphoma and dermal leukemic infiltrates respectively. Only 13 samples were processed for DNA PCR and all these samples were positive for MYC-IgH (c-gamma type) rearrangement. Only in one patient, in addition to c-gamma, c-alpha rearrangement was also detected.

CONCLUSION

The frequency (1.7%) and distribution of these translocations in our series and the association with 1q and 13q abnormalities is similar to the literature. Trisomies 7 and 12 were seen in less than 10% of our patients.

De Novo MYC and BCL2 Double-hit B-Cell Precursor Acute Lymphoblastic Leukemia (BCP-ALL) in Pediatric and Young Adult Patients Associated With Poor Prognosis

MYC and BCL2 translocations in B-cell lymphomas are defined as "double-hit" associated with poor prognosis in adult patients. Such double-hit events are extremely rare in B-cell precursor acute lymphoblastic leukemia (BCP-ALL), especially in pediatric patients or young adults. This study is to investigate the clinical manifestation of de novo MYCyBCL2 double-hit BCP-ALL in young patients. Two pediatric and one young adult patients were identified after a retrospective data review and all without previous history of lymphoma. There were two females and one male aged 15, 18, and 24, respectively. All patients had an unremarkable medical history before presenting with extensive bone marrow and central nervous system involvement at diagnosis. Flow cytometry immunophenotypic analysis showed an immature B-cell immunophenotype (CD10+, CD19+, TdT+, surface Ig-) and immunohistochemistry showed high expression of MYC and BCL2 in all cases. All patients showed complex karyotypes associated with 8q24 abnormalities in the form of t(8;9)(q24;p13) or t(8;14)(q24;q32) and t(14;18)(q32;q21) and fluorescence in situ hybridization confirmed MYC and BCL2 rearrangements. Two patients died of refractory disease or disease progression 7 and 13 months after initial diagnosis, respectively, and the third patient was treated with protocol AALL0232 under the Children's Oncology Group study, achieved complete remission and remained in remission for 53 months at last follow-up. Our study showed that De novo MYCyBCL2 double-hit BCP-ALL is a rare disease that also occurs in pediatric and young adult patients and associated with complex karyotypes and poor prognosis. Younger patients may benefit from intensified chemotherapy.

Translocation and deletion breakpoints in cancer genomes are associated with potential non-B DNA-forming sequences

Gross chromosomal rearrangements (including translocations, deletions, insertions and duplications) are a hallmark of cancer genomes and often create oncogenic fusion genes. An obligate step in the generation of such gross rearrangements is the formation of DNA double-strand breaks (DSBs). Since the genomic distribution of rearrangement breakpoints is non-random, intrinsic cellular factors may predispose certain genomic regions to breakage. Notably, certain DNA sequences with the potential to fold into secondary structures [potential non-B DNA structures (PONDS); e.g. triplexes, quadruplexes, hairpin/cruciforms, Z-DNA and single-stranded looped-out structures with implications in DNA replication and transcription] can stimulate the formation of DNA DSBs. Here, we tested the postulate that these DNA sequences might be found at, or in close proximity to, rearrangement breakpoints. By analyzing the distribution of PONDS-forming sequences within ±500 bases of 19 947 translocation and 46 365 sequence-characterized deletion breakpoints in cancer genomes, we find significant association between PONDS-forming repeats and cancer breakpoints. Specifically, (AT)_n, (GAA)_n and (GAAA)_n constitute the most frequent repeats at translocation breakpoints, whereas A-tracts occur preferentially at deletion breakpoints. Translocation breakpoints near PONDS-forming repeats also recur in different individuals and patient tumor samples. Hence, PONDS-forming sequences represent an intrinsic risk factor for genomic rearrangements in cancer genomes.

Double- and triple-hit lymphomas can present with features suggestive of immaturity, including TdT expression, and create diagnostic challenges

Double- and triple-hit lymphomas (DHL/THL) are aggressive B-cell neoplasms characterized by translocation of MYC with concurrent BCL2 and/or BCL6 translocation. In this retrospective study from one institution, we report clinicopathologic features of 13 cases (9 DHL/4 THL). The median age was 59 years (range 30-74) and patients included eight females and five males. Presentation included enlarging lymphadenopathy/masses (11 patients) and abnormal peripheral blood findings (2 patients). Features which raised the differential of an immature neoplasm included terminal deoxynucleotidyl transferase positivity (four cases, two THL/two DHL); dim CD45 expression (seven cases), lack of CD20 (two cases), or lack of surface immunoglobulin light chain (three cases) by flow cytometry; and blastoid morphology (two cases). We conclude that expression of TdT in a B-cell lymphoma with mature features or expression of surface light chain in a case otherwise suggestive of B-lymphoblastic leukemia/lymphoma should prompt an expedited evaluation for DHL/THL.

Supernumerary isochromosome 1, idic(1)(p12), leading to tetrasomy 1q in Burkitt lymphoma

Burkitt lymphoma (BL) is an aggressive mature B-cell neoplasm. The cytogenetic hallmark are MYC-involving translocations, most frequently as t(8;14)(q24;q32). Additional cytogenetic abnormalities are seen in the majority of cases. The most frequent additional aberration involves the long arm of chromosome 1, either as partial or complete trisomy 1q. A very rare additional aberration is a supernumerary isochromosome 1q, i(1)(q10), resulting in tetrasomy 1q. The biological significance of this aberration is unclear. We present a highly aggressive case of BL in a child with immature B-cell immunophenotype (IP) and supernumerary i(1)(q10). Diagnostic karyotyping showed 47,XY,+i(1)(q10),t(8;14)(q24;q32)[2]/47,idem,del(15)(q24)[21]/46,XY[2]. aCGH analysis detected a gain of 1p12qter and a loss of 15q22q25. FISH analysis confirmed the isodicentric chromosome 1, which has not previously been reported in BL. In the literature, supernumerary i(1)(q10) was found in 11 cases of which >80% presented with immature B-cell IP and >60% relapsed or died. Tetrasomy 1q resulting from supernumerary idic(1)(p12) or i(1)(q10) is a rare genetic event in BL and probably associated with immature B-cell IP. We propose that high amplification of genes on chromosome 1p12qter may contribute to the BL IP and disease progression.

A BACH2-BCL2L1 fusion gene resulting from a t(6;20)(q15;q11.2) chromosomal translocation in the lymphoma cell line BLUE-1

Abnormalities of the long arm of chromosome 6 are a common feature in various B-cell malignancies. In most cases, the genes involved have not yet been clearly identified. We have molecularly characterized the recently established Burkitt lymphoma cell line BLUE-1 that carries a t(6;20)(q15;q11.2) rearrangement in addition to the typical t(8;14) with MYC-IGH fusion. To identify the gene loci involved on both chromosomes we applied a sequential BAC clone mapping strategy. By using RT-PCR we were finally able to detect a chimeric mRNA transcript showing a fusion of the first (non-coding) exon of BACH2 (BTB and CNC homology 1, basic leucine zipper transcription factor 2) on 6q15 to the second exon of BCL2L1 (BCL-X) on 20q11. Various fusion transcripts were detected for different BCL2L1 (BCL-XL) isoforms. The fusion ultimately results in strong expression of the BCL2L1 (BCL-XL) anti-apoptosis protein, as demonstrated by immunoblotting. This is the first report that shows the involvement of both BCL2L1 and the transcription factor BACH2 in a chromosomal rearrangement. It points to BACH2 as a possibly important target in lymphomas with 6q aberrations, although other genes on 6q are probably also involved in these cases. Moreover, it suggests that members of the BCL2 anti-apoptosis gene family other than BCL2 itself might also be involved in lymphoma.

Diagnosis of Burkitt Lymphoma and Related High-Grade B-Cell Neoplasms

Burkitt lymphoma (BL) is an aggressive B-cell neoplasm with an extremely short doubling time that mainly affects children and young adults. Despite having several characteristic features, none is entirely specific for BL and the differential diagnosis may include diffuse large B-cell lymphoma (DLBCL), B lymphoblastic leukemia/lymphoma, and B-cell lymphoma unclassifiable with features intermediate between DLBCL and BL. We outline a practical approach to establish a diagnosis of BL and distinguish it from other high-grade B-cell malignancies. We pay particular attention to B-cell lymphomas with features intermediate between DLBCL and BL, a new diagnostic category in the 2008 World Health Organization classification system that provides a framework for categorizing challenging cases not meeting diagnostic criteria for either "classic" BL or DLBCL.

B-cell lymphomas with concurrent IGH-BCL2 and MYC rearrangements are aggressive neoplasms with clinical and pathologic features distinct from Burkitt lymphoma and diffuse large B-cell lymphoma

B-cell lymphomas with concurrent IGH-BCL2 and MYC rearrangements, also known as "double-hit" lymphomas (DHL), are rare neoplasms characterized by highly aggressive clinical behavior, complex karyotypes, and a spectrum of pathologic features overlapping with Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL) and B-lymphoblastic lymphoma/leukemia (B-LBL). The clinical and pathologic spectrum of this rare entity, including comparison to other high-grade B-cell neoplasms, has not been well defined. We conducted a retrospective analysis of clinical and pathologic features of 20 cases of DHL seen at our institution during a 5-year period. In addition, we carried out case-control comparisons of DHL with BL and International Prognostic Index (IPI)-matched DLBCL. The 11 men and 9 women had a median age of 63.5 years (range 32 to 91). Six patients had a history of grade 1 to 2 follicular lymphoma; review of the prior biopsy specimens in 2 of 5 cases revealed blastoid morphology. Eighteen patients had Ann Arbor stage 3 or 4 disease and all had elevated serum lactate dehydrogenase (LDH) levels at presentation. Extranodal disease was present in 17/20 (85%), bone marrow involvement in 10/17 (59%) and central nervous system (CNS) disease in 5/11 (45%). Nineteen patients were treated with combination chemotherapy, of whom 18 received rituximab and 14 received CNS-directed therapy. Fourteen patients (70%) died within 8 months of diagnosis. Median overall survival in the DHL group (4.5 mo) was inferior to both BL (P=0.002) and IPI-matched DLBCL (P=0.04) control patients. Twelve DHL cases (60%) were classified as B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL, 7 cases (35%) as DLBCL, not otherwise specified, and 1 case as B-LBL. Distinguishing features from BL included expression of Bcl2 (P<0.0001), Mum1/IRF4 (P=0.006), Ki-67 <95% (P<0.0001), and absence of EBV-EBER (P=0.006). DHL commonly contained the t(8;22) rather than the t(8;14) seen in most BL controls (P=0.001), and exhibited a higher number of chromosomal aberrations (P=0.0009). DHL is a high-grade B-cell neoplasm with a poor prognosis, resistance to multiagent chemotherapy, and clinical and pathologic features distinct from other high-grade B-cell neoplasms. Familiarity with the morphologic and immunophenotypic spectrum of DHL is important in directing testing to detect concurrent IGH-BCL2 and MYC rearrangements when a karyotype is unavailable. The aggressive clinical behavior and combination of genetic abnormalities seen in these cases may warrant categorization as a separate entity in future classifications and call for novel therapeutic approaches.

Monoclonal antibody therapy with rituximab for acute lymphoblastic leukemia

Significant advances have been achieved in the treatment of acute lymphoblastic leukemia (ALL) with the incorporation of targeted therapy agents. Targeting leukemia surface antigens with monoclonal antibodies is another promising strategy. This article comprehensively reviews available data regarding the use of rituximab for the treatment of Burkitt-type leukemia/lymphoma and CD20-positive precursor B-cell ALL. The incorporation of rituximab into frontline chemotherapy regimens for Burkitt-type leukemia/lymphoma appears to improve outcome. Preliminary data regarding the use of rituximab in frontline therapy for CD20- positive precursor B-cell ALL suggest its use may also be beneficial, particularly for the younger subsets.

Immunoglobulin light chain gene translocations in non-Hodgkin's lymphoma as assessed by fluorescence in situ hybridisation

In non-Hodgkin's lymphoma (NHL), the majority of translocations involve the immunoglobulin heavy chain gene (IGH) locus, while a few involve the immunoglobulin light chain gene (IGL) locus, consisting of the kappa light chain gene (IGkappa) and the lambda light chain gene (IGlambda). Although many reports have dealt with the translocation and/or amplification of IGH in NHL, only a few have identified IGL translocations. To identify cytogenetic abnormalities and the partner chromosomes of IGL translocations in NHL, we performed dual-colour fluorescence in situ hybridisation (DC-FISH) and spectral karyotyping (SKY) in seven NHL cell lines and 40 patients with NHL. We detected IGL translocations in two cell lines and nine patients: four patients with diffuse large B-cell lymphoma, three with follicular lymphoma, one with extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue and one with mantle cell lymphoma. Five distinct partners of IGlambda translocation were identified by SKY analysis: 3q27 in three patients, and 1p13, 6p25, 17p11.2 and 17q21 in one patient each. Three cases featured double translocations of IGH and IGL. These findings warrant the identification of novel genes 1p13, 6p25, 17p11.2 and 17q21.