B lymphoblastic leukaemia/lymphoma with KMT2A rearrangement

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Haematolymphoid Tumours (5th ed.)

editHAEM5 Conversion Notes
This page was converted to the new template on 2023-12-04. The original page can be found at HAEM4:B-Lymphoblastic Leukemia/Lymphoma with t(v;11q23.3); KMT2A-Rearranged.

Primary Author(s)*

Yassmine Akkari

Nicolas Millan

Cancer Category / Type

Precursor Lymphoid neoplasms

Cancer Sub-Classification / Subtype

B lymphoblastic leukemia/lymphoma with recurrent genetic abnormalities: MLL rearrangement

Definition / Description of Disease

B lymphoblastic leukemia/ lymphoma is the most common childhood cancer. Despite cure rates exceeding 90%, it remains an important cause of morbidity and mortality in adults and young children, especially when the disease relapses. It is a neoplasm of precursor cells (lymphoblasts) that are committed to the B-cell lineage. Blast cells are small to medium sized, with scant cytoplasm and inconspicuous nucleoli, mostly involving the bone marrow and peripheral blood. Occasionally, however, it can present with involvement of nodal and extra nodal sites (eg. lymph nodes and skin), at which point, it is more accurately referred to as B lymphoblastic lymphoma.

This class of the disease harbors a translocation between the MLL/KMT2A at 11q23 and any one of the large number of fusion partners. Patients with deletions of the MLL/KMT2A locus are not included in this group.

Synonyms / Terminology

MLL = KMT2A

With extensive bone marrow and peripheral blood involvement, B lymphoblastic leukemia is the most appropriate term. If, however, the disease presents as a mass lesion with minimal involvement of the bone marrow and peripheral blood, the term lymphoma should be used. When both sites are involved, the distinction between leukemia and lymphoma is arbitrary. A figure of 25% blasts in the bone marrow is used in some protocols as a threshold for defining leukemia.

Epidemiology / Prevalence

Etiology While the etiology of MLL translocations is unknown, there is strong evidence suggesting that it may occur in utero. These leukemias frequently affect very young infants, and this translocation is sometimes detected in blood spots of patients who later develop the disease. The MLL rearrangement is also seen in 85% of secondary leukemias that occur in patients treated with topoisomerase II inhibitors.

Epidemiology / Prevalence B-LBL/L is primarily a disease of children. 75% of cases occur in children under six years of age. The worldwide incidence is estimated at 1-5/100,000 persons per year.

MLL-rearranged B-ALL is often detected in infant leukemia and accounts for ~2% of all childhood ALLs. The outcome of MLL-R infant ALL remains poor with an event-free survival of 28-36% (Andersson AK et al., 2015 to be quoted in excel sheet). “MLL (mixed-lineage-leukemia) gene rearrangements at 11q23 are present in 80% of all infant B-ALL cases and 10% of all childhood B-ALL [38,39].”

Clinical Features

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Signs and Symptoms EXAMPLE Asymptomatic (incidental finding on complete blood counts)

EXAMPLE B-symptoms (weight loss, fever, night sweats)

EXAMPLE Fatigue

EXAMPLE Lymphadenopathy (uncommon)

Laboratory Findings EXAMPLE Cytopenias

EXAMPLE Lymphocytosis (low level)


editv4:Clinical Features
The content below was from the old template. Please incorporate above.

A substantial proportion of congenital leukemias, a subset of infant leukemias, harbors a rearrangement of the MLL gene (Moschiano E et al., 2016) MLL rearranged leukemia is associated with certain phenotypic features that distinguish them from other types of leukemia. MLL leukemias tend to be more aggressive, especially in infants, and more frequently present with hyperleukocytosis and central nervous system involvement.

Sites of Involvement

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Morphologic Features

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Immunophenotype

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Finding Marker
Positive (universal) EXAMPLE CD1
Positive (subset) EXAMPLE CD2
Negative (universal) EXAMPLE CD3
Negative (subset) EXAMPLE CD4

Chromosomal Rearrangements (Gene Fusions)

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Chromosomal Rearrangement Genes in Fusion (5’ or 3’ Segments) Pathogenic Derivative Prevalence Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
EXAMPLE t(9;22)(q34;q11.2) EXAMPLE 3'ABL1 / 5'BCR EXAMPLE der(22) EXAMPLE 20% (COSMIC)

EXAMPLE 30% (add reference)

Yes No Yes EXAMPLE

The t(9;22) is diagnostic of CML in the appropriate morphology and clinical context (add reference). This fusion is responsive to targeted therapy such as Imatinib (Gleevec) (add reference).

Individual Region Genomic Gain / Loss / LOH

Put your text here and fill in the table (Instructions: Includes aberrations not involving gene fusions. Can include references in the table. Can refer to CGC workgroup tables as linked on the homepage if applicable.)

Chr # Gain / Loss / Amp / LOH Minimal Region Genomic Coordinates [Genome Build] Minimal Region Cytoband Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
EXAMPLE

7

EXAMPLE Loss EXAMPLE

chr7:1- 159,335,973 [hg38]

EXAMPLE

chr7

Yes Yes No EXAMPLE

Presence of monosomy 7 (or 7q deletion) is sufficient for a diagnosis of AML with MDS-related changes when there is ≥20% blasts and no prior therapy (add reference).  Monosomy 7/7q deletion is associated with a poor prognosis in AML (add reference).

EXAMPLE

8

EXAMPLE Gain EXAMPLE

chr8:1-145,138,636 [hg38]

EXAMPLE

chr8

No No No EXAMPLE

Common recurrent secondary finding for t(8;21) (add reference).

Characteristic Chromosomal Patterns

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Chromosomal Pattern Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
EXAMPLE

Co-deletion of 1p and 18q

Yes No No EXAMPLE:

See chromosomal rearrangements table as this pattern is due to an unbalanced derivative translocation associated with oligodendroglioma (add reference).

Gene Mutations (SNV / INDEL)

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Gene; Genetic Alteration Presumed Mechanism (Tumor Suppressor Gene [TSG] / Oncogene / Other) Prevalence (COSMIC / TCGA / Other) Concomitant Mutations Mutually Exclusive Mutations Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
EXAMPLE: TP53; Variable LOF mutations

EXAMPLE:

EGFR; Exon 20 mutations

EXAMPLE: BRAF; Activating mutations

EXAMPLE: TSG EXAMPLE: 20% (COSMIC)

EXAMPLE: 30% (add Reference)

EXAMPLE: IDH1 R123H EXAMPLE: EGFR amplification EXAMPLE:  Excludes hairy cell leukemia (HCL) (add reference).


Note: A more extensive list of mutations can be found in cBioportal (https://www.cbioportal.org/), COSMIC (https://cancer.sanger.ac.uk/cosmic), ICGC (https://dcc.icgc.org/) and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

Epigenomic Alterations

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Genes and Main Pathways Involved

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Gene; Genetic Alteration Pathway Pathophysiologic Outcome
EXAMPLE: BRAF and MAP2K1; Activating mutations EXAMPLE: MAPK signaling EXAMPLE: Increased cell growth and proliferation
EXAMPLE: CDKN2A; Inactivating mutations EXAMPLE: Cell cycle regulation EXAMPLE: Unregulated cell division
EXAMPLE:  KMT2C and ARID1A; Inactivating mutations EXAMPLE:  Histone modification, chromatin remodeling EXAMPLE:  Abnormal gene expression program

Genetic Diagnostic Testing Methods

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Familial Forms

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Additional Information

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Links

KMT2A

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References

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Notes

*Primary authors will typically be those that initially create and complete the content of a page.  If a subsequent user modifies the content and feels the effort put forth is of high enough significance to warrant listing in the authorship section, please contact the CCGA coordinators (contact information provided on the homepage).  Additional global feedback or concerns are also welcome. *Citation of this Page: “B lymphoblastic leukaemia/lymphoma with KMT2A rearrangement”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated 12/4/2023, https://ccga.io/index.php/HAEM5:B_lymphoblastic_leukaemia/lymphoma_with_KMT2A_rearrangement.