HAEM5:Acute myeloid leukaemia with BCR::ABL1 fusion: Difference between revisions
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==Primary Author(s)*== | ==Primary Author(s)*== | ||
Xinxiu Xu, Vanderbilt University Medical Center | Xinxiu Xu PhD, PharmB, Vanderbilt University Medical Center | ||
==WHO Classification of Disease== | ==WHO Classification of Disease== | ||
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==Related Terminology== | ==Related Terminology== | ||
{| class="wikitable" | {| class="wikitable" | ||
|+ | |+ | ||
|Acceptable | |Acceptable | ||
| | |Acute myeloid leukaemia with t(9;22)(q34;q11.2) | ||
|- | |- | ||
|Not Recommended | |Not Recommended | ||
| | |N/A | ||
|} | |} | ||
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The t(9:22)(q34.1;q11.2) results in the formation of the Ph chromosome and the chimeric BCR-ABL1 fusion gene. In AML, ~70 - 80% cases with ''BCR::ABL1'' harbor p210 transcripts, and 50-60% cases with additional chromosomal abnormalities<ref name=":3">{{Cite journal|last=Soupir|first=Chad P.|last2=Vergilio|first2=Jo-Anne|last3=Dal Cin|first3=Paola|last4=Muzikansky|first4=Alona|last5=Kantarjian|first5=Hagop|last6=Jones|first6=Dan|last7=Hasserjian|first7=Robert P.|date=2007-04|title=Philadelphia chromosome-positive acute myeloid leukemia: a rare aggressive leukemia with clinicopathologic features distinct from chronic myeloid leukemia in myeloid blast crisis|url=https://pubmed.ncbi.nlm.nih.gov/17369142|journal=American Journal of Clinical Pathology|volume=127|issue=4|pages=642–650|doi=10.1309/B4NVER1AJJ84CTUU|issn=0002-9173|pmid=17369142}}</ref><ref name=":4">{{Cite journal|last=Konoplev|first=Sergej|last2=Yin|first2=C. Cameron|last3=Kornblau|first3=Steven M.|last4=Kantarjian|first4=Hagop M.|last5=Konopleva|first5=Marina|last6=Andreeff|first6=Michael|last7=Lu|first7=Gary|last8=Zuo|first8=Zhuang|last9=Luthra|first9=Rajyalakshmi|date=2013-01|title=Molecular characterization of de novo Philadelphia chromosome-positive acute myeloid leukemia|url=https://pubmed.ncbi.nlm.nih.gov/22691121|journal=Leukemia & Lymphoma|volume=54|issue=1|pages=138–144|doi=10.3109/10428194.2012.701739|issn=1029-2403|pmc=3925981|pmid=22691121}}</ref><ref>{{Cite journal|last=Nacheva|first=Ellie P.|last2=Grace|first2=Colin D.|last3=Brazma|first3=Diana|last4=Gancheva|first4=Katya|last5=Howard-Reeves|first5=Julie|last6=Rai|first6=Lena|last7=Gale|first7=Rosemary E.|last8=Linch|first8=David C.|last9=Hills|first9=Robert K.|date=2013-05|title=Does BCR/ABL1 positive acute myeloid leukaemia exist?|url=https://pubmed.ncbi.nlm.nih.gov/23521501|journal=British Journal of Haematology|volume=161|issue=4|pages=541–550|doi=10.1111/bjh.12301|issn=1365-2141|pmid=23521501}}</ref><ref name=":13">{{Cite journal|last=Orsmark-Pietras|first=Christina|last2=Landberg|first2=Niklas|last3=Lorenz|first3=Fryderyk|last4=Uggla|first4=Bertil|last5=Höglund|first5=Martin|last6=Lehmann|first6=Sören|last7=Derolf|first7=Åsa|last8=Deneberg|first8=Stefan|last9=Antunovic|first9=Petar|date=2021-06|title=Clinical and genomic characterization of patients diagnosed with the provisional entity acute myeloid leukemia with BCR-ABL1, a Swedish population-based study|url=https://pubmed.ncbi.nlm.nih.gov/33433047|journal=Genes, Chromosomes & Cancer|volume=60|issue=6|pages=426–433|doi=10.1002/gcc.22936|issn=1098-2264|pmid=33433047}}</ref>. The most common BCR-ABL1 transcripts p190 and p210 have been detected in nearly equal distribution<ref name=":2">{{Cite journal|last=Neuendorff|first=Nina Rosa|last2=Burmeister|first2=Thomas|last3=Dörken|first3=Bernd|last4=Westermann|first4=Jörg|date=2016|title=BCR-ABL-positive acute myeloid leukemia: a new entity? Analysis of clinical and molecular features|url=https://www.ncbi.nlm.nih.gov/pubmed/27297971|journal=Annals of Hematology|volume=95|issue=8|pages=1211–1221|doi=10.1007/s00277-016-2721-z|issn=1432-0584|pmid=27297971}}</ref>. Since p190 is very rare in CML (p210 transcripts in >99% of cases), the presentation with a p190 transcript is in favor of the diagnosis of AML rather than CML<ref name=":1">Arber DA, et al., (2017). Acute Myeloid Leukemia, in Hematopathology, 2nd Edition. Jaffe E, Arer DA, Campo E, Harris NL, and Quintanilla-Fend L, Editors. Elsevier:Philadelphia, PA, p817-846.</ref>. | |||
{| class="wikitable sortable" | {| class="wikitable sortable" | ||
|- | |- | ||
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!Clinical Relevance Details/Other Notes | !Clinical Relevance Details/Other Notes | ||
|- | |- | ||
| | |''ABL1''||''BCR::ABL1''||The pathogenic derivative is the der(22) resulting in fusion of 5’ BCR and 3’ABL1. | ||
| | |t(9;22)(q34;q11.2) | ||
|Common (CML); Rare (AML).<!-- The new version WHO indicates BCR::ABL1 is rare in AML, only accounts less than 0.5%, but the literature I found typically is 0.5-3%, the previous version also indicates the prevalence is <3%. Pls advice which number I should use. --> | |||
|Diagnosis: BCR-ABL1 positive AML is an emerging entity. The proliferation of ''BCR-ABL1'' positive blasts present a diagnostic dilemma. While it may be difficult, it is essential to distinguish between BCR-ABL1 positive AML and Chronic Myeloid Leukemia in Myeloid Blast Crisis (CML-MBC), in order to choose the most appropriate therapy (e.g., intensive induction chemotherapy versus tyrosine kinase inhibitor (TKI) followed by an early allogeneic stem cell transplant). After the exclusion of acute leukemia of ambiguous lineage (a separate entity according to WHO) by flow cytometry, it is helpful to note any past history of antecedent hematological disease. Compared to CML-MBC, a higher percentage of blasts (median: 47% vs 13%), a lower percentage of basophils (median: 0% vs 2.5%) and absolute basophil count, a lower frequency of splenomegaly (25% vs 65%), lower cellularity, fewer dwarf megakaryocytes, and normal M:E ratio favor the diagnosis of BCR-ABL1 positive AML<ref name=":4" /><ref name=":3" />. The detection of p190 transcript and the occurrence of any BCR-ABL1 transcript in less than 100% of metaphases supports the diagnosis of AML rather than CML. Persistent CCyR (Complete Cytogenetic Response) after conventional chemotherapy is unusual for CML-MBC and supports the diagnosis of BCR-ABL1 positive AML<ref name=":2" />. Karyotype analysis that identifies the t(9;22)(q34;q11.2) translocation, either alone or in conjunction with additional chromosomal abnormalities, characterizes BCR-ABL1 positive AML<ref name=":3" /><ref name=":4" />. In addition, molecular methods including dual-colour dual-fusion FISH, RT-PCR, qPCR, and RNA or DNA sequencing are used to identify all common breakpoint variants when applicable. | |||
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The | |||
Prognosis: The overall prognosis of BCR-ABL1 positive AML is poor, with a median survival time of <9 months<ref>{{Cite journal|last=Cuneo|first=A.|last2=Ferrant|first2=A.|last3=Michaux|first3=J. L.|last4=Demuynck|first4=H.|last5=Boogaerts|first5=M.|last6=Louwagie|first6=A.|last7=Doyen|first7=C.|last8=Stul|first8=M.|last9=Cassiman|first9=J. J.|date=1996|title=Philadelphia chromosome-positive acute myeloid leukemia: cytoimmunologic and cytogenetic features|url=https://pubmed.ncbi.nlm.nih.gov/8952155|journal=Haematologica|volume=81|issue=5|pages=423–427|issn=0390-6078|pmid=8952155}}</ref><ref name=":3" />. The National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology for AML categorize this entity into the poor-risk group, comparable with complex aberrant karyotype AML<ref name=":6">Pollyea DA, Altman JK, (2025). NCCN Clinical Practice Guidelines in Oncology: AML. Version 2. Available at: NCCN.org.</ref>. It appears that the prognosis of BCR-ABL1 positive AML depends more on the genetic background (concurrent aberrations) than on BCR-ABL1 itself. Unlike in CML, BCR-ABL1 does not appear to be the key driver in AML though may provide a proliferative advantage to a particular BCR-ABL1 positive subclone. | |||
Therapeutics: There is currently no standardized treatment approach for BCR-ABL1 positive AML. Therapy with TKI alone does not produce sustained responses in BCR-ABL1 positive AML<ref name=":3" />. This may be due to a very rapid clonal evolution, resulting in resistance in a much higher proportion of patients and in a significantly shorter time than in CML<ref name=":2" />.Venetoclax and TKI combination regimens have shown good response in some studies<ref>{{Cite journal|last=Maiti|first=Abhishek|last2=Franquiz|first2=Miguel J.|last3=Ravandi|first3=Farhad|last4=Cortes|first4=Jorge E.|last5=Jabbour|first5=Elias J.|last6=Sasaki|first6=Koji|last7=Marx|first7=Kayleigh|last8=Daver|first8=Naval G.|last9=Kadia|first9=Tapan M.|date=2020|title=Venetoclax and BCR-ABL Tyrosine Kinase Inhibitor Combinations: Outcome in Patients with Philadelphia Chromosome-Positive Advanced Myeloid Leukemias|url=https://pubmed.ncbi.nlm.nih.gov/32289808|journal=Acta Haematologica|volume=143|issue=6|pages=567–573|doi=10.1159/000506346|issn=1421-9662|pmc=7839068|pmid=32289808}}</ref>. | |||
|Yes (WHO, NCCN) | |||
|The t(9;22) is diagnostic of CML in the appropriate morphology and clinical context<ref>{{Cite journal|last=Cross|first=Nicholas C. P.|last2=Ernst|first2=Thomas|last3=Branford|first3=Susan|last4=Cayuela|first4=Jean-Michel|last5=Deininger|first5=Michael|last6=Fabarius|first6=Alice|last7=Kim|first7=Dennis Dong Hwan|last8=Machova Polakova|first8=Katerina|last9=Radich|first9=Jerald P.|date=2023-11|title=European LeukemiaNet laboratory recommendations for the diagnosis and management of chronic myeloid leukemia|url=https://pubmed.ncbi.nlm.nih.gov/37794101|journal=Leukemia|volume=37|issue=11|pages=2150–2167|doi=10.1038/s41375-023-02048-y|issn=1476-5551|pmc=10624636|pmid=37794101}}</ref><ref>{{Cite journal|last=Sawyers|first=C. L.|date=1999-04-29|title=Chronic myeloid leukemia|url=https://pubmed.ncbi.nlm.nih.gov/10219069|journal=The New England Journal of Medicine|volume=340|issue=17|pages=1330–1340|doi=10.1056/NEJM199904293401706|issn=0028-4793|pmid=10219069}}</ref>. The prevalence of BCR"" ABL1 in CML is common ~90-95%<ref>{{Cite journal|last=Sharma|first=Diwakar|last2=Wilson|first2=Christine|last3=Kumar|first3=Sachin|last4=Ghose|first4=Sampa|last5=Sahoo|first5=Ranjit|last6=Sharawat|first6=Surender K.|date=2024-08-01|title=Does presence of complex translocations involving BCR::ABL1 in chronic myeloid leukemia affect the response rate to tyrosine kinase inhibitors? A systematic review of the literature|url=https://linkinghub.elsevier.com/retrieve/pii/S1092913424000406|journal=Annals of Diagnostic Pathology|volume=71|pages=152303|doi=10.1016/j.anndiagpath.2024.152303|issn=1092-9134}}</ref>. This fusion is responsive to targeted therapy such as Imatinib (Gleevec)<ref>{{Cite journal|last=Cortes|first=Jorge E.|last2=Talpaz|first2=Moshe|last3=Giles|first3=Francis|last4=O'Brien|first4=Susan|last5=Rios|first5=Mary Beth|last6=Shan|first6=Jianqin|last7=Garcia-Manero|first7=Guillermo|last8=Faderl|first8=Stefan|last9=Thomas|first9=Deborah A.|date=2003-05-15|title=Prognostic significance of cytogenetic clonal evolution in patients with chronic myelogenous leukemia on imatinib mesylate therapy|url=https://pubmed.ncbi.nlm.nih.gov/12560227|journal=Blood|volume=101|issue=10|pages=3794–3800|doi=10.1182/blood-2002-09-2790|issn=0006-4971|pmid=12560227}}</ref>. | |||
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BCR::ABL1 is generally favorable in CML<ref>{{Cite journal|last=Branford|first=Susan|last2=Yeung|first2=David T.|last3=Parker|first3=Wendy T.|last4=Roberts|first4=Nicola D.|last5=Purins|first5=Leanne|last6=Braley|first6=Jodi A.|last7=Altamura|first7=Haley K.|last8=Yeoman|first8=Alexandra L.|last9=Georgievski|first9=Jasmina|date=2014-07-24|title=Prognosis for patients with CML and >10% BCR-ABL1 after 3 months of imatinib depends on the rate of BCR-ABL1 decline|url=https://pubmed.ncbi.nlm.nih.gov/24859364|journal=Blood|volume=124|issue=4|pages=511–518|doi=10.1182/blood-2014-03-566323|issn=1528-0020|pmid=24859364}}</ref><ref>{{Cite journal|last=Lauseker|first=Michael|last2=Hehlmann|first2=Rüdiger|last3=Hochhaus|first3=Andreas|last4=Saußele|first4=Susanne|date=2023-11|title=Survival with chronic myeloid leukaemia after failing milestones|url=https://pubmed.ncbi.nlm.nih.gov/37726340|journal=Leukemia|volume=37|issue=11|pages=2231–2236|doi=10.1038/s41375-023-02028-2|issn=1476-5551|pmc=10624616|pmid=37726340}}</ref>. | |||
Three BCR-ABL chimeric proteins result from varying mRNA fusions of the ABL and BCR genes. The most common breakpoint occurs in BCR intron 13 or 14, fusing to ABL1 exon a2 (e13a2, e14a2), yielding a 210 kilodalton protein (p210 BCR-ABL1) found in 95% of CML cases. A rare alternative (<1%) is the e19a2 fusion, producing a 230 kilodalton protein (p230 BCR-ABL1), a marker for neutrophilic-chronic myeloid leukemia. The e1a2 fusion results in the p190 BCR-ABL1 protein, prevalent in B cell ALL, less common in AML, and rare in CML<ref name=":5">{{Cite journal|last=Al Hamad|first=Mohammad|date=2021|title=Contribution of BCR-ABL molecular variants and leukemic stem cells in response and resistance to tyrosine kinase inhibitors: a review|url=https://pubmed.ncbi.nlm.nih.gov/35284066|journal=F1000Research|volume=10|pages=1288|doi=10.12688/f1000research.74570.2|issn=2046-1402|pmc=8886173|pmid=35284066}}</ref>. | |||
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The prevalence of BCR::ABL1 in AML is rare (~0.5 - 3%)<ref name=":5" />, per 5th WHO guideline the prevalence is <0.5%<ref>Tumours, 5th edition, IARC Press:Lyon, 2024. Online at: WHO Classification of Tumours.</ref>. | |||
< | There is a single case report of an AML patient with BCR::ABL1 achieving molecular remission with dasatinib and chemotherapy<ref>{{Cite journal|last=Shao|first=Xiaoyan|last2=Chen|first2=Dangui|last3=Xu|first3=Peipei|last4=Peng|first4=Miaoxin|last5=Guan|first5=Chaoyang|last6=Xie|first6=Pinhao|last7=Yuan|first7=Cuiying|last8=Chen|first8=Bing|date=2018-11|title=Primary Philadelphia chromosome positive acute myeloid leukemia: A case report|url=https://pubmed.ncbi.nlm.nih.gov/30383645|journal=Medicine|volume=97|issue=44|pages=e12949|doi=10.1097/MD.0000000000012949|issn=1536-5964|pmc=6221582|pmid=30383645}}</ref>. | ||
Outcome of patients < 50 years of age with TKI pretreated ''BCR::ABL1'' positive AML receiving allogeneic stem cell transplant is relatively favorable<ref>{{Cite journal|last=Lazarevic|first=Vladimir Lj|last2=Labopin|first2=Myriam|last3=Depei|first3=Wu|last4=Yakoub-Agha|first4=Ibrahim|last5=Huynh|first5=Anne|last6=Ljungman|first6=Per|last7=Schaap|first7=Nicolaas|last8=Cornelissen|first8=Jan J.|last9=Maillard|first9=Natacha|date=2018-01|title=Relatively favorable outcome after allogeneic stem cell transplantation for BCR-ABL1-positive AML: A survey from the acute leukemia working party of the European Society for blood and marrow transplantation (EBMT)|url=https://pubmed.ncbi.nlm.nih.gov/28971504|journal=American Journal of Hematology|volume=93|issue=1|pages=31–39|doi=10.1002/ajh.24928|issn=1096-8652|pmid=28971504}}</ref>. | |||
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</ | |||
Survival status postallogeneic transplantation appears similar to intermediate risk AML, with one report demonstrating 3 year overall survival of 73%<ref>{{Cite journal|last=Konoplev|first=Sergej|last2=Yin|first2=C. Cameron|last3=Kornblau|first3=Steven M.|last4=Kantarjian|first4=Hagop M.|last5=Konopleva|first5=Marina|last6=Andreeff|first6=Michael|last7=Lu|first7=Gary|last8=Zuo|first8=Zhuang|last9=Luthra|first9=Rajyalakshmi|date=2013-01|title=Molecular characterization of de novo Philadelphia chromosome-positive acute myeloid leukemia|url=https://pubmed.ncbi.nlm.nih.gov/22691121|journal=Leukemia & Lymphoma|volume=54|issue=1|pages=138–144|doi=10.3109/10428194.2012.701739|issn=1029-2403|pmc=3925981|pmid=22691121}}</ref>. | |||
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==Individual Region Genomic Gain/Loss/LOH== | |||
AML with BCR-ABL1 carries unique genome imbalances. Nacheva et al., used array comparative genomic hybridization (CGH) to perform a comparative study between several BCR-ABL1 positive entities. BCR-ABL1 positive AML displays characteristic of lymphoid disease (found in BCR-ABL1 positive ALL and CML): deletions of ''IKZF1'' and/or ''CDKN2A/B'' genes were recurrent findings in BCR-ABL1 positive AML as well as cryptic deletions within the immunoglobulin ''IGH'' and T cell receptor gene (''TRG alpha'') complexes<ref>{{Cite journal|last=Nacheva|first=Ellie P.|last2=Grace|first2=Colin D.|last3=Brazma|first3=Diana|last4=Gancheva|first4=Katya|last5=Howard-Reeves|first5=Julie|last6=Rai|first6=Lena|last7=Gale|first7=Rosemary E.|last8=Linch|first8=David C.|last9=Hills|first9=Robert K.|date=2013|title=Does BCR/ABL1 positive acute myeloid leukaemia exist?|url=https://www.ncbi.nlm.nih.gov/pubmed/23521501|journal=British Journal of Haematology|volume=161|issue=4|pages=541–550|doi=10.1111/bjh.12301|issn=1365-2141|pmid=23521501}}</ref>. Importantly, these aberrations were found to be absent in CML-MBC and hence they are potentially a helpful diagnostic tool for difficult cases. | |||
Most cases will have monosomy 7/Del(7q), trisomy 8 or complex karyotypes in addition to the t(9;22)(q34.1;q11.2)<ref name=":0">Arber DA, et al., (2017). Acute myeloid leukaemia with recurrent genetic abnormalities, in World Health Organization Classification of Tumours of Haematopoietic and Lymphoid Tissues, Revised 4th edition. Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J, Arber DA, Hasserjian RP, Le Beau MM, Orazi A, and Siebert R, Editors. Revised 4th Edition. IARC Press: Lyon, France, p140.</ref>. | |||
{| class="wikitable sortable" | {| class="wikitable sortable" | ||
|- | |- | ||
! | !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 | |||
|- | |- | ||
|7|| | |7 | ||
|Loss | |||
|chr7 | |||
|''IKZF1,'' TR Beta Chain (TRB) genes<!-- Pls advice if this is correct, thx --> | |||
|D,P | |||
|No | |||
|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<ref name=":6" />. | |||
|- | |- | ||
|8 | |8 | ||
| | |Gain | ||
|chr8 | |||
|Unknown | |||
< | |D,P | ||
---- | |No | ||
</ | |Common recurrent secondary finding for t(8;21)<ref>{{Cite journal|last=Jakovic|first=Ljubomir|last2=Fekete|first2=Marija Dencic|last3=Virijevic|first3=Marijana|last4=Kurtovic|first4=Nada Kraguljac|last5=Todoric-Zivanovic|first5=Biljana|last6=Stamatovic|first6=Dragana|last7=Karan-Djurasevic|first7=Teodora|last8=Pavlovic|first8=Sonja|last9=Lekovic|first9=Danijela|date=2022-09-01|title=De novo acute myeloid leukemia harboring concomitant t(8;21)(q22;q22);RUNX1::RUNX1T1 and BCR::ABL1 (p190 minor transcript)|url=https://link.springer.com/article/10.1007/s12308-022-00509-4|journal=Journal of Hematopathology|language=en|volume=15|issue=3|pages=191–195|doi=10.1007/s12308-022-00509-4|issn=1865-5785}}</ref><ref>{{Cite journal|last=Singh|first=Manish K.|last2=Gupta|first2=Ruchi|last3=Rahman|first3=Khaliqur|last4=Kumar|first4=Sanjeev|last5=Sharma|first5=Akhilesh|last6=Nityanand|first6=Soniya|date=2017-03-01|title=Co-existence of AML1-ETO and BCR-ABL1 transcripts in a relapsed patient of acute myeloid leukemia with favorable risk group: A coincidence or clonal evolution?|url=https://www.sciencedirect.com/science/article/pii/S1658387616000054|journal=Hematology/Oncology and Stem Cell Therapy|volume=10|issue=1|pages=39–41|doi=10.1016/j.hemonc.2015.12.003|issn=1658-3876}}</ref>. | ||
|}<br /> | |||
==Characteristic Chromosomal or Other Global Mutational Patterns== | ==Characteristic Chromosomal or Other Global Mutational Patterns== | ||
Additional chromosomal aberrations are infrequently seen in BCR-ABL AML, it has been described together with different class II aberrations such as CBFB-MYH11, RUNX1- RUNX1T1 and PML-RARA<ref name=":12" /><ref name=":2" />. In AML, BCR-ABL1 seems to cooperate with several AML-specific aberrations such as inv(16), t(8;21) and myelodysplasia-related cytogenetic aberrations<ref name=":2" /><ref name=":12">{{Cite journal|last=Bacher|first=Ulrike|last2=Haferlach|first2=Torsten|last3=Alpermann|first3=Tamara|last4=Zenger|first4=Melanie|last5=Hochhaus|first5=Andreas|last6=Beelen|first6=Dietrich W.|last7=Uppenkamp|first7=Michael|last8=Rummel|first8=Mathias|last9=Kern|first9=Wolfgang|date=2011|title=Subclones with the t(9;22)/BCR-ABL1 rearrangement occur in AML and seem to cooperate with distinct genetic alterations|url=https://www.ncbi.nlm.nih.gov/pubmed/21275954|journal=British Journal of Haematology|volume=152|issue=6|pages=713–720|doi=10.1111/j.1365-2141.2010.08472.x|issn=1365-2141|pmid=21275954}}</ref>. (For diagnostic purpose, note that inv(16) is not restricted to AML and can also be found in CML-MBC). Additional chromosomal aberrations, such as an additional Ph chromosome, trisomy 19 and isochromosome 17q seen in CML MBP are infrequently seen in AML with ''BCR::ABL1.''<!-- how to align left??? --> | |||
{| class="wikitable sortable" | {| class="wikitable sortable" | ||
|- | |- | ||
!Chromosomal Pattern | !Chromosomal Pattern | ||
!Molecular Pathogenesis | !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 | ||
|- | |- | ||
| | |inv(16)(p13.1q22) or t(16;16)(p13.1;q22) | ||
|CBFB::MYH11 fusion | |||
|< | |Rare (BCR-ABL1 AML) | ||
|D,P | |||
|< | |No<!-- Here, is it for Inv(16) in BCR-ABL1 patient or in all AML patients? --> | ||
|The rarity of Philadelphia-positive subclones in AML patients with specific genetic lesions requires more cases for conclusive prognosis and therapeutic insights<ref name=":12" />. | |||
|- | |- | ||
| | |t(8;21)(q22;q22.1) | ||
|RUNX1- RUNX1T1 | |||
| | |Rare (BCR-ABL1 AML) | ||
| | |D,P | ||
|< | |No | ||
|The rarity of Philadelphia-positive subclones in AML patients with specific genetic lesions requires more cases for conclusive prognosis and therapeutic insights<ref name=":12" />. | |||
|- | |- | ||
| | |t(15;17)(q13.4;q21.2) | ||
| | |PML-RARA | ||
| | |Rare (BCR-ABL1 AML) | ||
| | |D,P | ||
| | |No | ||
| | |The rarity of Philadelphia-positive subclones in AML patients with specific genetic lesions requires more cases for conclusive prognosis and therapeutic insights<ref name=":12" />. | ||
| | |- | ||
|AML-myelodysplasia-related (AML-MR) cytogenetic aberrations: | |||
• del(5q), t(5q) | |||
• inv(3)(q21q26) | |||
• ‐7, del(7q) | |||
|Unknown | |||
|Rare (BCR-ABL1 AML) | |||
|D,P | |||
|No | |||
|The rarity of Philadelphia-positive subclones in AML patients with specific genetic lesions requires more cases for conclusive prognosis and therapeutic insights<ref name=":12" />. | |||
< | In AML, BCR-ABL appears to interact with specific aberrations like inv(16) and myelodysplasia-related cytogenetic changes, like del(5q), t(5q)<ref name=":12" />, inv(3)(q21q26)<ref name=":12" />, ‐7, del(7q)<ref>{{Cite journal|last=Tirado|first=Carlos A.|last2=Valdez|first2=Federico|last3=Klesse|first3=Laura|last4=Karandikar|first4=Nitin J.|last5=Uddin|first5=Naseem|last6=Arbini|first6=Arnaldo|last7=Fustino|first7=Nicholas|last8=Collins|first8=Robert|last9=Patel|first9=Sangeeta|date=2010-07|title=Acute myeloid leukemia with inv(16) with CBFB–MYH11, 3′CBFB deletion, variant t(9;22) with BCR–ABL1, and del(7)(q22q32) in a pediatric patient: case report and literature review|url=https://doi.org/10.1016/j.cancergencyto.2010.03.001|journal=Cancer Genetics and Cytogenetics|volume=200|issue=1|pages=54–59|doi=10.1016/j.cancergencyto.2010.03.001|issn=0165-4608}}</ref>, but the mechanisms of disease initiation and cooperation remain unclear<ref name=":2" />. | ||
< | |}<br /> | ||
</ | |||
==Gene Mutations (SNV/INDEL)== | ==Gene Mutations (SNV/INDEL)== | ||
''RUNX1'' mutation is common in AML with ''BCR::ABL1'' and occurs in ~40% of cases<ref name=":13" />. Other mutated genes include ''ASXL1, BCOR, IDH1 / IDH2'' and ''SRSF2''; each of these occur in 10 - 15% of cases<ref name=":14">{{Cite journal|last=Konoplev|first=Sergej|last2=Yin|first2=C. Cameron|last3=Kornblau|first3=Steven M.|last4=Kantarjian|first4=Hagop M.|last5=Konopleva|first5=Marina|last6=Andreeff|first6=Michael|last7=Lu|first7=Gary|last8=Zuo|first8=Zhuang|last9=Luthra|first9=Rajyalakshmi|date=2013-01|title=Molecular characterization of de novo Philadelphia chromosome-positive acute myeloid leukemia|url=https://pubmed.ncbi.nlm.nih.gov/22691121|journal=Leukemia & Lymphoma|volume=54|issue=1|pages=138–144|doi=10.3109/10428194.2012.701739|issn=1029-2403|pmc=3925981|pmid=22691121}}</ref><ref name=":15">{{Cite journal|last=Eisfeld|first=A.-K.|last2=Mrózek|first2=K.|last3=Kohlschmidt|first3=J.|last4=Nicolet|first4=D.|last5=Orwick|first5=S.|last6=Walker|first6=C. J.|last7=Kroll|first7=K. W.|last8=Blachly|first8=J. S.|last9=Carroll|first9=A. J.|date=2017-10|title=The mutational oncoprint of recurrent cytogenetic abnormalities in adult patients with de novo acute myeloid leukemia|url=https://pubmed.ncbi.nlm.nih.gov/28321123|journal=Leukemia|volume=31|issue=10|pages=2211–2218|doi=10.1038/leu.2017.86|issn=1476-5551|pmc=5628133|pmid=28321123}}</ref><ref name=":13" />.Coinciding molecular events such as ''NPM1'' mutations have been reported<ref name=":12" />. Mutations of ''FLT3'' or ''DNMT3A'' are not commonly detected<ref name=":13" />. | |||
{| class="wikitable sortable" | {| class="wikitable sortable" | ||
|- | |- | ||
!Gene!! | !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 | ||
|- | |- | ||
| | |''RUNX1'' | ||
<br /> | <br /> | ||
| | |Variable LOF and missense mutations | ||
| | |Tumor Suppressor Gene | ||
| | |Common (BCR-ABL1 AML) | ||
|D,P | |||
|No | |||
| | |AML with ''RUNX1'' mutation is associated with a poorer prognosis<ref name=":6" />. ''RUNX1'' was the most commonly mutated gene, altered in eight of 21 BCR-ABL1 AML cases (38%)<ref name=":13" />. | ||
| | Mutations in five genes (''BCOR, BCORL1, SF3B1, SRSF2,'' and ''STAG2''), along with ''ASXL1'' and ''RUNX1'' mutations, are linked to the proposed high-risk AML chromatin-spliceosome group<ref name=":13" />. | ||
| | |||
|- | |- | ||
|''ASXL1'' | |||
|Variable LOF and missense mutations | |||
|Tumor Suppressor Gene | |||
|Recurrent (BCR-ABL1 AML) | |||
|D,P | |||
|No | |||
|Mutations in five genes (''BCOR, BCORL1, SF3B1, SRSF2,'' and ''STAG2''), along with ''ASXL1'' and ''RUNX1'' mutations, are linked to the proposed high-risk AML chromatin-spliceosome group<ref name=":13" />. | |||
|- | |- | ||
|'' | |''BCOR'' | ||
| | |Variable LOF and missense mutations | ||
|Tumor Suppressor Gene | |||
|Recurrent (BCR-ABL1 AML) | |||
|D,P | |||
|No | |||
|Mutations in five genes (''BCOR, BCORL1, SF3B1, SRSF2,'' and ''STAG2''), along with ''ASXL1'' and ''RUNX1'' mutations, are linked to the proposed high-risk AML chromatin-spliceosome group<ref name=":13" />. | |||
|- | |- | ||
|''IDH1 / IDH2'' | |||
|Missense | |||
|Oncogene | |||
|Recurrent (BCR-ABL1 AML) | |||
|D,P | |||
|No | |||
|Other mutated genes include ''ASXL1, BCOR, IDH1 / IDH2'' and ''SRSF2''; each of these occur in 10 - 15% of cases<ref name=":14" /><ref name=":15" /><ref name=":13" />. | |||
|- | |- | ||
| | |''SRSF2'' | ||
|Missense and in frame del | |||
|Tumor Suppressor Gene | |||
|Recurrent (BCR-ABL1 AML) | |||
|D,P | |||
|No | |||
|Mutations in five genes (''BCOR, BCORL1, SF3B1, SRSF2,'' and ''STAG2''), along with ''ASXL1'' and ''RUNX1'' mutations, are linked to the proposed high-risk AML chromatin-spliceosome group<ref name=":13" />. | |||
|- | |- | ||
| | |''NPM1'' | ||
|- | |Variable LOF | ||
| | |Tumor Suppressor Gene and Oncogene | ||
| | |Rare (BCR-ABL1 AML) | ||
|D,P | |||
< | |No | ||
< | |Philadelphia-positive subclones can emerge in ''NPM1''-mutated AML at diagnosis or during follow-up, and may cooperate with the ''NPM1'' mutation like other class I mutations, such as ''FLT3-''ITD or ''MLL-''PTD<ref name=":12" />. | ||
|}Note: A more extensive list of mutations can be found in [https://www.cbioportal.org/ <u>cBioportal</u>], [https://cancer.sanger.ac.uk/cosmic <u>COSMIC</u>], and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content. | |||
==Epigenomic Alterations== | ==Epigenomic Alterations== | ||
| Line 357: | Line 236: | ||
The ''BCR'' gene product has serine/threonine kinase activity and is a GTPase-activating protein for p21rac<ref name=":7">{{Cite journal|last=Maru|first=Y.|last2=Witte|first2=O. N.|date=1991|title=The BCR gene encodes a novel serine/threonine kinase activity within a single exon|url=https://www.ncbi.nlm.nih.gov/pubmed/1657398|journal=Cell|volume=67|issue=3|pages=459–468|doi=10.1016/0092-8674(91)90521-y|issn=0092-8674|pmid=1657398}}</ref>. The ''ABL1'' gene is a proto-oncogene that encodes a protein tyrosine kinase involved in a variety of cellular processes, including cell division, adhesion, differentiation, and response to stress. The activity of this protein is negatively regulated by its SH3 domain, whereby deletion of the region encoding this domain results in an oncogene<ref name=":8">{{Cite journal|last=Wang|first=Jean Y. J.|date=2014|title=The capable ABL: what is its biological function?|url=https://www.ncbi.nlm.nih.gov/pubmed/24421390|journal=Molecular and Cellular Biology|volume=34|issue=7|pages=1188–1197|doi=10.1128/MCB.01454-13|issn=1098-5549|pmc=3993570|pmid=24421390}}</ref>. The t(9,22)(q34;q11) leads to the formation of a Philadelphia chromosome and generates an active chimeric BCR-ABL1 tyrosine kinase. The fusion gene is created by juxtaposing the ''ABL1'' gene on chromosome 9 (region q34) to a part of ''BCR'' (breakpoint cluster region) gene on chromosome 22 (region q11). This is a reciprocal translocation, creating an elongated chromosome 9 (der 9), and a truncated chromosome 22 (the Philadelphia chromosome, 22q-), the oncogenic BCR-ABL1 being found on the shorter derivative 22 chromosome<ref name=":9">{{Cite journal|last=Kurzrock|first=Razelle|last2=Kantarjian|first2=Hagop M.|last3=Druker|first3=Brian J.|last4=Talpaz|first4=Moshe|date=2003|title=Philadelphia chromosome-positive leukemias: from basic mechanisms to molecular therapeutics|url=https://www.ncbi.nlm.nih.gov/pubmed/12755554|journal=Annals of Internal Medicine|volume=138|issue=10|pages=819–830|doi=10.7326/0003-4819-138-10-200305200-00010|issn=1539-3704|pmid=12755554}}</ref><ref name=":10">{{Cite journal|last=Melo|first=J. V.|date=1996|title=The diversity of BCR-ABL fusion proteins and their relationship to leukemia phenotype|url=https://www.ncbi.nlm.nih.gov/pubmed/8839828|journal=Blood|volume=88|issue=7|pages=2375–2384|issn=0006-4971|pmid=8839828}}</ref>. This gene encodes for a BCR-ABL1 fusion protein, a tyrosine kinase. Tyrosine kinase activities are typically regulated in an auto-inhibitory manner, but the BCR-ABL1 fusion gene codes for a protein that is continuously activated, causing unregulated cell division. This is a result of the replacement of the myristoylated cap region which causes a conformational change rendering the kinase domain inactive, with a truncated portion of the BCR protein<ref name=":11">{{Cite journal|last=Nagar|first=Bhushan|last2=Hantschel|first2=Oliver|last3=Young|first3=Matthew A.|last4=Scheffzek|first4=Klaus|last5=Veach|first5=Darren|last6=Bornmann|first6=William|last7=Clarkson|first7=Bayard|last8=Superti-Furga|first8=Giulio|last9=Kuriyan|first9=John|date=2003|title=Structural basis for the autoinhibition of c-Abl tyrosine kinase|url=https://www.ncbi.nlm.nih.gov/pubmed/12654251|journal=Cell|volume=112|issue=6|pages=859–871|doi=10.1016/s0092-8674(03)00194-6|issn=0092-8674|pmid=12654251}}</ref>. The enzyme is responsible for the uncontrolled growth of leukemic cells which survive better than normal blood cells. As a result of BCR/ABL1 variable splicing (fusion RNA and hybrid proteins), two transcripts p190 and p210 are found for BCR-ABL1 positive AML. | |||
{| class="wikitable sortable" | {| class="wikitable sortable" | ||
|- | |- | ||
!Gene; Genetic Alteration!!Pathway!!Pathophysiologic Outcome | !Gene; Genetic Alteration!!Pathway!!Pathophysiologic Outcome | ||
|- | |- | ||
| | |''BCR'' and ''ABL1''; Activating mutations | ||
| | |Ras/MAPK, PI3K/AKT, JAK/STAT and NF-kappaB pathways | ||
|The BCR-ABL fusion protein is an constitutively active tyrosine kinase that triggers multiple pathways, promoting unchecked cell proliferation and survival. | |||
| | |||
|} | |} | ||
< | <br /> | ||
[[File:BCR-ABL1 translocation image.jpg|Figure 1. Philadelphia chromosome. A piece of chromosome 9 and a piece of chrosomome 22 break off and trade places. The BCR-ABL1 gene is formed on chromosome 22 where the piece of chromosome 9 attaches. The changed chromosome 22 is called Philadelphia chromosome. Image from National Cancer Institute website https://www.cancer.gov/publications/dictionaries/cancer-terms/def/bcr-abl-fusion-gene|frame|alt=|none]][[File:Screenshot 2025-05-11 181714.png|thumb|Figure 2. Signal transduction pathway of the BCR-ABL fusion gene|alt=|none]] | |||
---- | |||
==Genetic Diagnostic Testing Methods== | ==Genetic Diagnostic Testing Methods== | ||
Bone marrow with myeloid blasts >20% combined with detection of t(9,22) by | Bone marrow with myeloid blasts >20% combined with detection of t(9,22) by karyotype analysis or BCR-ABL1 using FISH or reverse transcriptase-quantitative PCR (RT-qPCR) and RNA or DNA seq<ref name=":2" />. A graphic of the clinical path for the differential diagnosis of BCR-ABL1 positive acute myeloid leukemia and chronic myeloid leukemia-myeloid blast crisis (CML-MBC) is presented<ref name=":2" />. | ||
==Familial Forms== | ==Familial Forms== | ||
| Line 410: | Line 270: | ||
==References== | ==References== | ||
<references /> | |||
<br /> | <br /> | ||