Mixed-phenotype acute leukaemia with BCR::ABL1 fusion
Haematolymphoid Tumours (WHO Classification, 5th ed.)
 | This page is under construction |
editContent Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition ClassificationThis page was converted to the new template on 2023-12-07. The original page can be found at HAEM4:Mixed Phenotype Acute Leukemia (MPAL) with t(9;22)(q34.1;q11.2); BCR-ABL1.
(General Instructions – The focus of these pages is the clinically significant genetic alterations in each disease type. This is based on up-to-date knowledge from multiple resources such as PubMed and the WHO classification books. The CCGA is meant to be a supplemental resource to the WHO classification books; the CCGA captures in a continually updated wiki-stye manner the current genetics/genomics knowledge of each disease, which evolves more rapidly than books can be revised and published. If the same disease is described in multiple WHO classification books, the genetics-related information for that disease will be consolidated into a single main page that has this template (other pages would only contain a link to this main page). Use HUGO-approved gene names and symbols (italicized when appropriate), HGVS-based nomenclature for variants, as well as generic names of drugs and testing platforms or assays if applicable. Please complete tables whenever possible and do not delete them (add N/A if not applicable in the table and delete the examples); to add (or move) a row or column in a table, click nearby within the table and select the > symbol that appears. Please do not delete or alter the section headings. The use of bullet points alongside short blocks of text rather than only large paragraphs is encouraged. Additional instructions below in italicized blue text should not be included in the final page content. Please also see Author_Instructions and FAQs as well as contact your Associate Editor or Technical Support.)
Primary Author(s)*
Tracy Tucker, PhD, FCCMG
WHO Classification of Disease
| Structure | Disease |
|---|---|
| Book | Haematolymphoid Tumours (5th ed.) |
| Category | Myeloid proliferations and neoplasms |
| Family | Acute leukaemias of mixed or ambiguous lineage |
| Type | Acute leukaemia of ambiguous lineage with defining genetic abnormalities |
| Subtype(s) | Mixed-phenotype acute leukaemia with BCR::ABL1 fusion |
WHO Essential and Desirable Genetic Diagnostic Criteria
(Instructions: The table will have the diagnostic criteria from the WHO book autocompleted; remove any non-genetics related criteria. If applicable, add text about other classification systems that define this entity and specify how the genetics-related criteria differ.)
| WHO Essential Criteria (Genetics)* | |
| WHO Desirable Criteria (Genetics)* | |
| Other Classification |
*Note: These are only the genetic/genomic criteria. Additional diagnostic criteria can be found in the WHO Classification of Tumours.
Related Terminology
(Instructions: The table will have the related terminology from the WHO autocompleted.)
| Acceptable | |
| Not Recommended |
Gene Rearrangements
Put your text here and fill in the table (Instructions: Details on clinical significance such as prognosis and other important information can be provided in the notes section. Please include references throughout the table. Do not delete the table.)
| Driver Gene | Fusion(s) and Common Partner Genes | Molecular Pathogenesis | Typical Chromosomal Alteration(s) | Prevalence -Common >20%, Recurrent 5-20% or Rare <5% (Disease) | Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes |
|---|---|---|---|---|---|---|---|
| EXAMPLE: ABL1 | EXAMPLE: BCR::ABL1 | EXAMPLE: The pathogenic derivative is the der(22) resulting in fusion of 5’ BCR and 3’ABL1. | EXAMPLE: t(9;22)(q34;q11.2) | EXAMPLE: Common (CML) | EXAMPLE: D, P, T | EXAMPLE: Yes (WHO, NCCN) | 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). BCR::ABL1 is generally favorable in CML (add reference). |
| EXAMPLE: CIC | EXAMPLE: CIC::DUX4 | EXAMPLE: Typically, the last exon of CIC is fused to DUX4. The fusion breakpoint in CIC is usually intra-exonic and removes an inhibitory sequence, upregulating PEA3 genes downstream of CIC including ETV1, ETV4, and ETV5. | EXAMPLE: t(4;19)(q25;q13) | EXAMPLE: Common (CIC-rearranged sarcoma) | EXAMPLE: D | EXAMPLE:
DUX4 has many homologous genes; an alternate translocation in a minority of cases is t(10;19), but this is usually indistinguishable from t(4;19) by short-read sequencing (add references). | |
| EXAMPLE: ALK | EXAMPLE: ELM4::ALK
|
EXAMPLE: Fusions result in constitutive activation of the ALK tyrosine kinase. The most common ALK fusion is EML4::ALK, with breakpoints in intron 19 of ALK. At the transcript level, a variable (5’) partner gene is fused to 3’ ALK at exon 20. Rarely, ALK fusions contain exon 19 due to breakpoints in intron 18. | EXAMPLE: N/A | EXAMPLE: Rare (Lung adenocarcinoma) | EXAMPLE: T | EXAMPLE:
Both balanced and unbalanced forms are observed by FISH (add references). | |
| EXAMPLE: ABL1 | EXAMPLE: N/A | EXAMPLE: Intragenic deletion of exons 2–7 in EGFR removes the ligand-binding domain, resulting in a constitutively active tyrosine kinase with downstream activation of multiple oncogenic pathways. | EXAMPLE: N/A | EXAMPLE: Recurrent (IDH-wildtype Glioblastoma) | EXAMPLE: D, P, T | ||
editv4:Chromosomal Rearrangements (Gene Fusions)The content below was from the old template. Please incorporate above.
Almost all cases have a t(9;22) identified by karyotype analysis or a BCR-ABL1 fusion identified by FISH analysis. At the molecular level, the p190 fusion transcript is more common than the p210.
| Chromosomal Rearrangement | Genes in Fusion (5’ or 3’ Segments) | Pathogenic Derivative | Prevalence |
|---|---|---|---|
| t(9;22)(q34;q11.2) | 3'ABL1 / 5'BCR | der(22) | 2-5% of AML cases and 25% of all MPAL |
End of V4 Section
editv4:Clinical Significance (Diagnosis, Prognosis and Therapeutic Implications).Please incorporate this section into the relevant tables found in:
- Chromosomal Rearrangements (Gene Fusions)
- Individual Region Genomic Gain/Loss/LOH
- Characteristic Chromosomal Patterns
- Gene Mutations (SNV/INDEL)
Diagnostic:
• The presence of t(9;22)(q34.1;q11.2) with mixed phenotype immune-profile is diagnostic of a cytogenetic subtype of MPAL.
Prognostic:
• t(9;22)(q34.1;q11.2) MPAL have a poor prognosis and appears to be worse than that of the other MPALs[1][2]. It is unclear if patients with MPAL and t(9;22) have a worse prognosis than t(9;22)-positive ALL, however, some data exists to suggest that treatment with tyrosine kinase inhibitors would have a similar effect in MPAL as in ALL[3].
Therapeutic Target:
• Tyrosine kinase inhibitors such as imatinib or dasatinib.
• There are no biological factors that predict a patient’s response to tyrosine kinase inhibitors.
End of V4 Section
Individual Region Genomic Gain/Loss/LOH
Put your text here and fill in the table (Instructions: Includes aberrations not involving gene rearrangements. Details on clinical significance such as prognosis and other important information can be provided in the notes section. Can refer to CGC workgroup tables as linked on the homepage if applicable. Please include references throughout the table. Do not delete the table.)
| Chr # | Gain, Loss, Amp, LOH | Minimal Region Cytoband and/or Genomic Coordinates [Genome Build; Size] | Relevant Gene(s) | Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes |
|---|---|---|---|---|---|---|
| EXAMPLE:
7 |
EXAMPLE: Loss | EXAMPLE:
chr7 |
EXAMPLE:
Unknown |
EXAMPLE: D, P | EXAMPLE: 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 references). |
| EXAMPLE:
8 |
EXAMPLE: Gain | EXAMPLE:
chr8 |
EXAMPLE:
Unknown |
EXAMPLE: D, P | EXAMPLE:
Common recurrent secondary finding for t(8;21) (add references). | |
| EXAMPLE:
17 |
EXAMPLE: Amp | EXAMPLE:
17q12; chr17:39,700,064-39,728,658 [hg38; 28.6 kb] |
EXAMPLE:
ERBB2 |
EXAMPLE: D, P, T | EXAMPLE:
Amplification of ERBB2 is associated with HER2 overexpression in HER2 positive breast cancer (add references). Add criteria for how amplification is defined. | |
editv4:Genomic Gain/Loss/LOHThe content below was from the old template. Please incorporate above.
Deletions including IKZF1 (7p12.2) have been reported in MPAL with t(9;22)[4].
End of V4 Section
Characteristic Chromosomal or Other Global Mutational Patterns
Put your text here and fill in the table (Instructions: Included in this category are alterations such as hyperdiploid; gain of odd number chromosomes including typically chromosome 1, 3, 5, 7, 11, and 17; co-deletion of 1p and 19q; complex karyotypes without characteristic genetic findings; chromothripsis; microsatellite instability; homologous recombination deficiency; mutational signature pattern; etc. Details on clinical significance such as prognosis and other important information can be provided in the notes section. Please include references throughout the table. Do not delete the table.)
| Chromosomal Pattern | Molecular Pathogenesis | Prevalence -
Common >20%, Recurrent 5-20% or Rare <5% (Disease) |
Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes |
|---|---|---|---|---|---|
| EXAMPLE:
Co-deletion of 1p and 18q |
EXAMPLE: See chromosomal rearrangements table as this pattern is due to an unbalanced derivative translocation associated with oligodendroglioma (add reference). | EXAMPLE: Common (Oligodendroglioma) | EXAMPLE: D, P | ||
| EXAMPLE:
Microsatellite instability - hypermutated |
EXAMPLE: Common (Endometrial carcinoma) | EXAMPLE: P, T | |||
editv4:Characteristic Chromosomal Aberrations / PatternsThe content below was from the old template. Please incorporate above.
Many cases have other cytogenetic abnormalities in addition to the t(9;22) or a complex karyotype.
End of V4 Section
Gene Mutations (SNV/INDEL)
Put your text here and fill in the table (Instructions: This table is not meant to be an exhaustive list; please include only genes/alterations that are recurrent or common as well either disease defining and/or clinically significant. If a gene has multiple mechanisms depending on the type or site of the alteration, add multiple entries in the table. For clinical significance, denote associations with FDA-approved therapy (not an extensive list of applicable drugs) and NCCN or other national guidelines if applicable; Can also refer to CGC workgroup tables as linked on the homepage if applicable as well as any high impact papers or reviews of gene mutations in this entity. Details on clinical significance such as prognosis and other important information such as concomitant and mutually exclusive mutations can be provided in the notes section. Please include references throughout the table. Do not delete the table.)
| Gene | Genetic Alteration | Tumor Suppressor Gene, Oncogene, Other | Prevalence -
Common >20%, Recurrent 5-20% or Rare <5% (Disease) |
Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes |
|---|---|---|---|---|---|---|
| EXAMPLE:EGFR
|
EXAMPLE: Exon 18-21 activating mutations | EXAMPLE: Oncogene | EXAMPLE: Common (lung cancer) | EXAMPLE: T | EXAMPLE: Yes (NCCN) | EXAMPLE: Exons 18, 19, and 21 mutations are targetable for therapy. Exon 20 T790M variants cause resistance to first generation TKI therapy and are targetable by second and third generation TKIs (add references). |
| EXAMPLE: TP53; Variable LOF mutations
|
EXAMPLE: Variable LOF mutations | EXAMPLE: Tumor Supressor Gene | EXAMPLE: Common (breast cancer) | EXAMPLE: P | EXAMPLE: >90% are somatic; rare germline alterations associated with Li-Fraumeni syndrome (add reference). Denotes a poor prognosis in breast cancer. | |
| EXAMPLE: BRAF; Activating mutations | EXAMPLE: Activating mutations | EXAMPLE: Oncogene | EXAMPLE: Common (melanoma) | EXAMPLE: T | ||
Note: A more extensive list of mutations can be found in cBioportal, COSMIC, and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.
editv4:Gene Mutations (SNV/INDEL)The content below was from the old template. Please incorporate above.
Not known in this specific subgroup.
End of V4 Section
Epigenomic Alterations
Not known in this specific subgroup.
Genes and Main Pathways Involved
Put your text here and fill in the table (Instructions: Please include references throughout the table. Do not delete the table.)
| 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 |
editv4:Genes and Main Pathways InvolvedThe content below was from the old template. Please incorporate above.
Genes:
• ABL1 on 9q34.12 is transcribed from centromere to telomere. It encodes a protein tyrosine kinase (SH1) which is regulated by its SH (SRC homology) domains (SH2, SH3) and has a DNA binding motif that is regulated by CDC2-mediated phosphorylation. It is widely expressed and has mainly a nuclear localization.
• BCR on 22q11.2 is transcribed from centromere to telomere. Its exact function is still unclear; it is known to contain an oligomerization domain, serine/threonine kinase activity, Rho guanine nucleotide exchange factor (RHO-GEF) domain, pleckstrin homology (PH) domain and a RAC-GAP domain. It is widely expressed and has mainly a cytoplasmic localization.
DNA:
• t(9;22)(q34.1;q11.2) results in a 5’BCR-3’ABL1 hybrid gene with the functional fusion residing on the derivative 22. Several variants of the BCR-ABL1 fusion transcript are known. The most common variant (major variant, p210) fuses either BCR exon 13 or BCR exon 14 to ABL1 exon 2 (b2a2 and b3a2 respectively). The minor variant fuses BCR exon 1 to ABL1 exon 2 (p190, e1a2) whereas the micro variant fuses BCR exon 19 to ABL1 exon 2 (p230, e19a2). Fusions involving other exons of BCR or ABL1 are also possible.
Protein:
• The p210 protein consists of amino acids 1-902 (or 927) from BCR linked to amino acid 1096 of ABL1. Both the p210 and p230 fusion proteins contain the RHO-GEF and PH domains from BCR, and the SH2 and SH3 domains, the kinase domain (SH1) and the DNA binding domain from ABL1. The fusion protein is predominantly located in nuclei and has constitutive kinase activity mediated by the oligomerization domain from BCR.
Key cellular pathways:
• The chimeric protein encoded by the BCR-ABL1 fusion gene has constitutive kinase activity resulting in activation of the Ras signal transduction pathway.
• The PI3-K (phosphatidyl inositol 3' kinase) pathway is also activated via Ras.
• The aberrant signaling results in enhanced cellular proliferation of leukemic progenitors, inhibition of apoptosis and provokes cell adhesive abnormalities.
End of V4 Section
Genetic Diagnostic Testing Methods
• Chromosome analysis, FISH, RT-PCR
• FISH or RT-PCR is needed for cytogenetically cryptic cases with typical immunophenotype
• RT-PCR is employed for minimal residual disease detection
Familial Forms
None
Additional Information
None
Links
References
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- ↑ Matutes, Estella; et al. (2011). "Mixed-phenotype acute leukemia: clinical and laboratory features and outcome in 100 patients defined according to the WHO 2008 classification". Blood. 117 (11): 3163–3171. doi:10.1182/blood-2010-10-314682. ISSN 1528-0020. PMID 21228332.
- ↑ Killick, S.; et al. (1999). "Outcome of biphenotypic acute leukemia". Haematologica. 84 (8): 699–706. ISSN 0390-6078. PMID 10457405.
- ↑ Kawajiri, Chika; et al. (2014). "Successful treatment of Philadelphia chromosome-positive mixed phenotype acute leukemia by appropriate alternation of second-generation tyrosine kinase inhibitors according to BCR-ABL1 mutation status". International Journal of Hematology. 99 (4): 513–518. doi:10.1007/s12185-014-1531-0. ISSN 1865-3774. PMID 24532437.
- ↑ Yan, Lingzhi; et al. (2012). "Clinical, immunophenotypic, cytogenetic, and molecular genetic features in 117 adult patients with mixed-phenotype acute leukemia defined by WHO-2008 classification". Haematologica. 97 (11): 1708–1712. doi:10.3324/haematol.2012.064485. ISSN 1592-8721. PMC 3487445. PMID 22581002.
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 Associate Editor or other CCGA representative. When pages have a major update, the new author will be acknowledged at the beginning of the page, and those who contributed previously will be acknowledged below as a prior author.
Prior Author(s):
*Citation of this Page: “Mixed-phenotype acute leukaemia with BCR::ABL1 fusion”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated 02/11/2025, https://ccga.io/index.php/HAEM5:Mixed-phenotype_acute_leukaemia_with_BCR::ABL1_fusion.