Distinctive genotypes in infants with T-cell acute lymphoblastic leukaemia.

Infant T-cell acute lymphoblastic leukaemia (iT-ALL) is a very rare and poorly defined entity with a poor prognosis. We assembled a unique series of 13 infants with T-ALL, which allowed us to identify genotypic abnormalities and to investigate prenatal origins. Matched samples (diagnosis/remission) were analysed by single nucleotide polymorphism-array to identify genomic losses and gains. In three cases, we identified a recurrent somatic deletion on chromosome 3. These losses result in the complete deletion of MLF1 and have not previously been described in T-ALL. We observed two cases with an 11p13 deletion (LMO2-related), one of which also harboured a deletion of RB1. Another case presented a large 11q14·1-11q23·2 deletion that included ATM and only five patients (38%) showed deletions of CDKN2A/B. Four cases showed NOTCH1 mutations; in one case FBXW7 was the sole mutation and three cases showed alterations in PTEN. KMT2A rearrangements (KMT2A-r) were detected in three out of 13 cases. For three patients, mutations and copy number alterations (including deletion of PTEN) could be backtracked to birth using neonatal blood spot DNA, demonstrating an in utero origin. Overall, our data indicates that iT-ALL has a diverse but distinctive profile of genotypic abnormalities when compared to T-ALL in older children and adults.

De novo reciprocal translocation t(5;11)(q22;p15) associated with hydrops fetalis (reciprocal translocation and hydrops fetalis).

OBJECTIVE: This is a case of a prenatally diagnosed non-immune hydrops fetalis (NIHF) associated with translocation t(5;11)(q22;p15). An association between NIHF and this translocation has not been reported previously. CASE REPORT: The patient was referred to the perinatology clinic with hydrops fetalis diagnosis at 23 weeks' gestation. We noted that the fetus had bilateral pleural effusion, ascites, widespread subcutaneous edema, membranous ventricular septal defect, hypoplastic fifth finger middle phalanx, clinodactyly, single umbilical artery. We performed cordocentesis. Chromosomal analysis on blood showed a balanced translocation between the long arm of chromosome 5 and the short arm of chromosome 11 with karyotype of 46,XX,t(5;11)(q22;p15). CONCLUSION: We present prenatal diagnosis of a de novo translocation (5;11) in a hydropic fetus with ultrason abnormalities. In our case, karyotype analysis of the fetus, mother and father provided evidence of a de novo translocation, that might explain the NIHF.

Distinct nuclear orientation patterns for mouse chromosome 11 in normal B lymphocytes.

BACKGROUND: Characterizing the nuclear orientation of chromosomes in the three-dimensional (3D) nucleus by multicolor banding (mBANDing) is a new approach towards understanding nuclear organization of chromosome territories. An mBANDing paint is composed of multiple overlapping subchromosomal probes that represent different regions of a single chromosome. In this study, we used it for the analysis of chromosome orientation in 3D interphase nuclei. We determined whether the nuclear orientation of the two chromosome 11 homologs was random or preferential, and if it was conserved between diploid mouse Pre B lymphocytes of BALB/c origin and primary B lymphocytes of congenic [T38HxBALB/c]N wild-type mice. The chromosome orientation was assessed visually and through a semi-automated quantitative analysis of the radial and angular orientation patterns observed in both B cell types. RESULTS: Our data indicate that there are different preferential patterns of chromosome 11 orientation, which are not significantly different between both mouse cell types (p > 0.05). In the most common case for both cell types, both copies of chromosome 11 were oriented in parallel with the nuclear border. The second most common pattern in both types of B lymphocytes was with one homolog of chromosome 11 positioned with its telomeric end towards the nuclear center and with its centromeric end towards the periphery, while the other chromosome 11 was found parallel with the nuclear border. In addition to these two most common orientations present in approximately 50% of nuclei from each cell type, other orientations were observed at lower frequencies. CONCLUSIONS: We conclude that there are probabilistic, non-random orientation patterns for mouse chromosome 11 in the mouse B lymphocytes we investigated (p < 0.0001).

CLL/SLL diagnosed in an adolescent.

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is a disease of older adults. Pediatric CLL/SLL is vanishingly rare in the literature. We present a case of CLL/SLL diagnosed in a 17-year-old male. The pathologic findings of this case were those of classic CLL/SLL with an ATM deletion, a characteristic genetic abnormality in CLL/SLL. Management guidelines for CLL/SLL are tailored to older adults making determination of the optimal therapy for this patient a unique challenge.

Patients with chronic lymphocytic leukaemia and clonal deletion of both 17p13.1 and 11q22.3 have a very poor prognosis.

Detection of a 17p13.1 deletion (loss of TP53) or 11q22.3 deletion (loss of ATM), by fluorescence in situ hybridization (FISH), in chronic lymphocytic leukaemia (CLL) patients is associated with a poorer prognosis. Because TP53 and ATM are integral to the TP53 pathway, we hypothesized that 17p13.1- (17p-) and 11q22.3- (11q-) occurring in the same cell (clonal 17p-/11q-) would confer a worse prognosis than either 17p- or 11q-. We studied 2184 CLL patients with FISH (1995-2012) for the first occurrence of 17p-, 11q-, or clonal 17p-/11q-. Twenty (1%) patients had clonal 17p-/11q-, 158 (7%) had 17p- (including 4 with 17p- and 11q- in separate clones), 247 (11%) had 11q-, and 1759 (81%) had neither 17p- nor 11q-. Eleven of 15 (73%) tested patients with clonal 17p-/11q- had dysfunctional TP53 mutations. Overall survival for clonal 17p-/11q- was significantly shorter (1·9 years) than 17p- (3·1 years, P = 0·04), 11q- (4·8 years, P ≤ 0·0001), or neither 17p- nor 11q- (9·3 years, P ≤ 0·0001). Clonal 17p-/11q- thus conferred significantly worse prognosis, suggesting that loss of at least one copy of both TP53 and ATM causes more aggressive disease. Use of an ATM/TP53 combination FISH probe set could identify these very-high risk patients.

Mantle cell lymphoma: 2013 Update on diagnosis, risk-stratification, and clinical management.

DISEASE OVERVIEW: Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood, and bone marrow with a short remission duration to standard therapies and a median overall survival of 4-5 years. DIAGNOSIS: Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t(11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma. RISK STRATIFICATION: The Mantle Cell Lymphoma International Prognostic Index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median overall survival (OS) for the low risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 months and 29 months for the high risk group. RISK-ADAPTED THERAPY: For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytarabine containing regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor) or lenalidamide (anti-angiogenesis) are approved agents. Clinical trials with Ibruitinib (Bruton's Tyrosine Kinase inhibitor) or Idelalisib (PI3K inhibitor) have demonstrated excellent clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients.

Human KVLQT1 gene shows tissue-specific imprinting and encompasses Beckwith-Wiedemann syndrome chromosomal rearrangements.

Genomic imprinting is an epigenetic chromosomal modification in the gamete or zygote causing preferential expression of a specific parental allele in somatic cells of the offspring. We and others have identified three imprinted human genes on 11p15.5, IGF2, H19, and p57KIP2, although the latter gene is separated by 700 kb from the other two, and it is unclear whether there are other imprinted genes within this large interval. We previously mapped an embryonal tumour suppressor gene to this region, as well as five balanced germline chromosomal rearrangement breakpoints from patients with Beckwith-Wiedemann syndrome (BWS), a condition characterized by prenatal overgrowth and cancer. We isolated the upstream exons of the previously identified gene KVLQT1, which causes the familial cardiac defect long-QT (LQT) syndrome. We found that KVLQT1 spans much of the interval between p57KIP2 and IGF2, and that it is also imprinted. We demonstrated that the gene is disrupted by chromosomal rearrangements in BWS patients, as well as by a balanced chromosomal translocation in an embryonal rhabdoid tumour. Furthermore, the lack of parent-of-origin effect in LQT syndrome appears to be due to relative lack of imprinting in the affected tissue, cardiac muscle, representing a novel mechanism for variable penetrance of a human disease gene.

Mantle cell lymphoma: 2012 update on diagnosis, risk-stratification, and clinical management.

DISEASE OVERVIEW: Mantle cell lymphoma (MCL) is a non-Hodgkin lymphoma characterized by involvement of the lymph nodes, spleen, blood, and bone marrow with a short remission duration to standard therapies and a median overall survival of 4-5 years. DIAGNOSIS: Diagnosis is based on lymph node, bone marrow, or tissue morphology of centrocytic lymphocytes, small cell type, or blastoid variant cells. A chromosomal translocation t(11:14) is the molecular hallmark of MCL, resulting in the overexpression of cyclin D1. Cyclin D1 is detected by immunohistochemistry in 98% of cases. The absence of SOX-11 or a low Ki-67 may correlate with a more indolent form of MCL. The differential diagnosis of MCL includes small lymphocytic lymphoma, marginal zone lymphoma, and follicular lymphoma. RISK STRATIFICATION: The mantle cell lymphoma international prognostic index (MIPI) is the prognostic model most often used and incorporates ECOG performance status, age, leukocyte count, and lactic dehydrogenase. A modification of the MIPI also adds the Ki-67 proliferative index if available. The median overall survival (OS) for the low-risk group was not reached (5-year OS of 60%). The median OS for the intermediate risk group was 51 and 29 months for the high-risk group. RISK-ADAPTED THERAPY: For selected indolent, low MIPI MCL patients, initial observation may be appropriate therapy. For younger patients with intermediate or high risk MIPI MCL, aggressive therapy with a cytarabine containing regimen ± autologous stem cell transplantation should be considered. For older MCL patients with intermediate or high risk MIPI, combination chemotherapy with R-CHOP, R-Bendamustine, or a clinical trial should be considered. At the time of relapse, agents directed at activated pathways in MCL cells such as bortezomib (NFkB inhibitor), BTK inhibitors or CAL-101 (B-cell receptor inhibitors) or lenalidamide (antiangiogenesis) have clinical activity in MCL patients. Autologous or allogeneic stem cell transplantation can also be considered in young patients.

Complex and cryptic chromosomal rearrangements involving the MLL gene in acute leukemia: a study of 7 patients and review of the literature.

Chromosomal rearrangements involving the MLL gene have been associated with many different types of hematological malignancies. Most of them are easily recognized by conventional cytogenetics. However, in some cases, complex, unusual or cryptic rearrangements make the MLL involvement difficult or impossible to be detected by conventional cytogenetics. Fluorescent in situ hybridization with a panel of probes coupled with long distance inverse-PCR was used to identify chromosomal rearrangements involving the MLL gene. Seven unusual chromosomal rearrangements were identified, including two complex translocations, three insertions of material of chromosome 11 in another chromosome and one insertion of chromosome material into the MLL gene. Conventional cytogenetics showed three patients to have a deletion of 11q; one had an unexpected t(6;11)(q27;q23) whereas the other two patients had also an insertion of MLL material in another chromosome. Concurrent 3' deletion in the MLL rearrangement was observed in two patients. We recommend a systematic approach to be used in all cases of acute leukemia starting with FISH analyses using a commercially available MLL split signal probe. Should an abnormality be discovered, the analysis has to be completed by further molecular cytogenetic and genomic PCR methods in order to unravel the recombination mechanism.

A novel spliced fusion of MLL with CT45A2 in a pediatric biphenotypic acute leukemia.

BACKGROUND: Abnormalities of 11q23 involving the MLL gene are found in approximately 10% of human leukemias. To date, nearly 100 different chromosome bands have been described in rearrangements involving 11q23 and 64 fusion genes have been cloned and characterized at the molecular level. In this work we present the identification of a novel MLL fusion partner in a pediatric patient with de novo biphenotypic acute leukemia. METHODS: Cytogenetics, fluorescence in situ hybridization (FISH), molecular studies (RT-PCR and LDI-PCR), and bioinformatic sequence analysis were used to characterize the CT45A2 gene as novel MLL fusion partner in pediatric acute leukemia. RESULTS: Fluorescence in situ hybridization of bone marrow G-banded metaphases demonstrated a cryptic insertion of 11q23 in Xq26.3 involving the MLL gene. Breakpoint fusion analysis revealed that a DNA fragment of 653 kb from 11q23, containing MLL exons 1-9 in addition to 16 other 11q23 genes, was inserted into the upstream region of the CT45A2 gene located at Xq26.3. In addition, a deletion at Xq26.3 encompassing the 3' region of the DDX26B gene (exons 9-16) and the entire CT45A1 gene was identified. RNA analysis revealed the presence of a novel MLL-CT45A2 fusion transcript in which the first 9 exons of the MLL gene were fused in-frame to exon 2 of the CT45A2 gene, resulting in a spliced MLL fusion transcript with an intact open reading frame. The resulting chimeric transcript predicts a fusion protein where the N-terminus of MLL is fused to the entire open reading frame of CT45A2. Finally, we demonstrate that all breakpoint regions are rich in long repetitive motifs, namely LINE/L1 and SINE/Alu sequences, but all breakpoints were exclusively identified outside these repetitive DNA sequences. CONCLUSION: We have identified CT45A2 as a novel spliced MLL fusion partner in a pediatric patient with de novo biphenotypic acute leukemia, as a result of a cryptic insertion of 11q23 in Xq26.3. Since CT45A2 is the first Cancer/Testis antigen family gene found fused with MLL in acute leukemia, future studies addressing its biologic relevance for leukemogenesis are warranted.

Mixed phenotype acute leukemia with t(11;19)(q23;p13.3)/ MLL-MLLT1(ENL), B/T-lymphoid type: A first case report.

The majority of cases of acute leukemia belong to a specific lineage origin, either lymphoid or myeloid, and therefore are classified as acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML), based on morphologic features and cytochemical and immunophenotypic profile of the blast cells. A minority of acute leukemias however, show no clear evidence of differentiation along a single lineage. These are now classified under acute leukemias of ambiguous lineage by the most recent WHO classification and account for <4% of all cases of acute leukemia [1]. They include leukemias with no lineage specific antigens (acute undifferentiated leukemias) and those with blasts that express antigens of more than one lineage to such degree that it is not possible to assign the leukemia to any one particular lineage with certainty (mixed phenotype acute leukemias). The latter can either be leukemias with two distinct populations of blasts, each expressing antigens of a different lineage (historically referred to as "bilineal" leukemias) or a single blast population expressing antigens of multiple lineages (historically referred to as "biphenotypic" acute leukemias) [2]. Acute leukemias of ambiguous lineage may harbor a variety of genetic lesions. Those with t(9;22)(q34;q11) or translocations associated with mixed lineage leukemias (MLL) gene, i.e., t(11;V)(q23;V), occur frequently enough and are associated with distinct features, that are considered as separate entities according to the recent WHO classification. Co-expression of myeloid and B-lymphoid antigens is most common in mixed phenotype acute leukemia (MPAL), followed by co-expression of myeloid and T-lymphoid antigens, accounting for 66-70% and 23-24% of MLLs, respectively. Coexpression of B- and T-lineage associated antigens or antigens of all three lineages is exceedingly rare, accounting for <5% of MLLs [3,4]. The requirements for assigning more than one lineage to a single blast population has been established by current WHO classification [1].

MYC amplification on double minute chromosomes in plasma cell leukemia with double IGH/CCND1 fusion genes.

In multiple myeloma (MM), MYC rearrangements that result in increased MYC expression are associated with an aggressive form of MM and adverse outcome. However, the consequences of MYC amplification in MM remain unclear. Here, we describe an unusual case of plasma cell leukemia (PCL) harboring MYC amplification on double minute chromosomes (dmin). A 79-year-old woman was initially diagnosed as having BJP-κ type MM with bone lesions. After seven months, the disease progressed to secondary PCL: leukocytes 49.1 × 109/L with 77% plasma cells showing lymphoplasmacytic appearance. The bone marrow was infiltrated with 76% plasma cells immunophenotypically positive for CD38 and negative for CD45, CD19, CD20, and CD56. The karyotype by G-banding and spectral karyotyping was 48,XX,der(14)t(11;14)(q13;q32),+der(14)t(14;19)(q32;q13.1),+18,6~95dmin[15]/46,XX[5]. Fluorescence in situ hybridization detected multiple MYC signals on dmin and double IGH/CCND1 fusion signals on der(14)t(11;14) and der(14)t(14;19). Most plasma cells were diffusely and strongly positive for MYC and CCND1 by immunohistochemistry. The patient died of progressive disease after one week. MYC amplification led to high expression of MYC and rapid disease progression, indicating its clinical significance in the pathogenesis of MM/PCL. MYC amplification on dmin may be a very rare genetic event closely associated with the progression to PCL and coexistence of IGH/CCND1 fusions.