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{{DISPLAYTITLE:Chronic myeloid leukaemia}}

{{DISPLAYTITLE:Chronic myeloid leukaemia}}

[[HAEM5:Table_of_Contents|Haematolymphoid Tumours (5th ed.)]]

[[HAEM5:Table_of_Contents|Haematolymphoid Tumours (WHO Classification, 5th ed.)]]

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<span style="color:#0070C0">(General Instructions – The main focus of these pages is the clinically significant genetic alterations in each disease type. Use [https://www.genenames.org/ <u>HUGO-approved gene names and symbols</u>] (italicized when appropriate), [https://varnomen.hgvs.org/ 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). 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 </span><u>[[Author_Instructions]]</u><span style="color:#0070C0"> and [[Frequently Asked Questions (FAQs)|<u>FAQs</u>]] as well as contact your [[Leadership|<u>Associate Editor</u>]] or [mailto:CCGA@cancergenomics.org <u>Technical Support</u>])</span>

<span style="color:#0070C0">(General Instructions – The main focus of these pages is the clinically significant genetic alterations in each disease type. Use [https://www.genenames.org/ <u>HUGO-approved gene names and symbols</u>] (italicized when appropriate), [https://varnomen.hgvs.org/ 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 to a table, click nearby within the table and select the > symbol that appears to be given options. 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 </span><u>[[Author_Instructions]]</u><span style="color:#0070C0"> and [[Frequently Asked Questions (FAQs)|<u>FAQs</u>]] as well as contact your [[Leadership|<u>Associate Editor</u>]] or [mailto:CCGA@cancergenomics.org <u>Technical Support</u>])</span>

==Primary Author(s)*==

==Primary Author(s)*==

==Clinical Features==

==Clinical Features==

Put your text here and fill in the table <span style="color:#0070C0">(''Instruction: Can include references in the table'') </span>

Put your text here and fill in the table <span style="color:#0070C0">(''Instruction: Can include references in the table. Do not delete table.'') </span>

{| class="wikitable"

{| class="wikitable"

|'''Signs and Symptoms'''

|'''Signs and Symptoms'''

|EXAMPLE Asymptomatic (incidental finding on complete blood counts)

|<span class="blue-text">EXAMPLE:</span> Asymptomatic (incidental finding on complete blood counts)

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

<span class="blue-text">EXAMPLE:</span> B-symptoms (weight loss, fever, night sweats)

EXAMPLE Fatigue

<span class="blue-text">EXAMPLE:</span> Fatigue

EXAMPLE Lymphadenopathy (uncommon)

<span class="blue-text">EXAMPLE:</span> Lymphadenopathy (uncommon)

|-

|-

|'''Laboratory Findings'''

|'''Laboratory Findings'''

|EXAMPLE Cytopenias

|<span class="blue-text">EXAMPLE:</span> Cytopenias

EXAMPLE Lymphocytosis (low level)

<span class="blue-text">EXAMPLE:</span> Lymphocytosis (low level)

|}

|}

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<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|Content Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition Classification}}

Approximately 50% of the patients who are diagnosed with CML are asymptomatic and diagnosed during the routine blood tests.<ref name=":0">Silver RT. Molecular Biology of CML. In: Kufe DW, Pollock RE, Weichselbaum RR, et al., editors. Holland-Frei Cancer Medicine. 6th edition. Hamilton (ON): BC Decker; 2003. Available from: <nowiki>https://www.ncbi.nlm.nih.gov/books/NBK13554/</nowiki></ref> CML is a hematological disease that occurs predominantly in adults but in rare cases, it can occur in the pediatric population.<ref>{{Cite journal|last=Am|first=Mendizabal|last2=P|first2=Garcia-Gonzalez|last3=Ph|first3=Levine|date=2013|title=Regional Variations in Age at Diagnosis and Overall Survival Among Patients With Chronic Myeloid Leukemia From Low and Middle Income Countries|url=https://pubmed.ncbi.nlm.nih.gov/23411044/|language=en|pmid=23411044}}</ref> The onset of CML is insidious. Patients with CML usually experience dragging sensation of the abdomen due to splenomegaly. The clinical hallmark of CML is the uncontrolled proliferation of mature and maturing granulocytes at all stages of maturation: metamyelocytes, myelocytes, promyelocytes, and myeloblasts. Patients with CML usually begin with the initial chronic phase before entering the terminal blastic phase and 60-80% of the patients go through accelerated phase before reaching the terminal blastic phase. In chronic phase, CML patients show abnormal routine blood tests with clinical symptoms such as unintentional weight loss, loss of appetite, satiety, fatigue, insomnia and palpable splenomegaly. In rare cases, hyperviscosity syndrome can be a manifestation with a wide spectrum of features such as priapism, tinnitus, hearing loss, cerebral accidents and blindness. In the blastic phase, CML leukemic cells resemble acute leukemic cells morphologically. CNS and lymph node involvement are notable in the blastic phase of CML. If untreated, CML patients will progress to the terminal blastic phase in 3 to 5 years.   

Approximately 50% of the patients who are diagnosed with CML are asymptomatic and diagnosed during the routine blood tests.<ref name=":0">Silver RT. Molecular Biology of CML. In: Kufe DW, Pollock RE, Weichselbaum RR, et al., editors. Holland-Frei Cancer Medicine. 6th edition. Hamilton (ON): BC Decker; 2003. Available from: <nowiki>https://www.ncbi.nlm.nih.gov/books/NBK13554/</nowiki></ref> CML is a hematological disease that occurs predominantly in adults but in rare cases, it can occur in the pediatric population.<ref>{{Cite journal|last=Am|first=Mendizabal|last2=P|first2=Garcia-Gonzalez|last3=Ph|first3=Levine|date=2013|title=Regional Variations in Age at Diagnosis and Overall Survival Among Patients With Chronic Myeloid Leukemia From Low and Middle Income Countries|url=https://pubmed.ncbi.nlm.nih.gov/23411044/|language=en|pmid=23411044}}</ref> The onset of CML is insidious. Patients with CML usually experience dragging sensation of the abdomen due to splenomegaly. The clinical hallmark of CML is the uncontrolled proliferation of mature and maturing granulocytes at all stages of maturation: metamyelocytes, myelocytes, promyelocytes, and myeloblasts. Patients with CML usually begin with the initial chronic phase before entering the terminal blastic phase and 60-80% of the patients go through accelerated phase before reaching the terminal blastic phase. In chronic phase, CML patients show abnormal routine blood tests with clinical symptoms such as unintentional weight loss, loss of appetite, satiety, fatigue, insomnia and palpable splenomegaly. In rare cases, hyperviscosity syndrome can be a manifestation with a wide spectrum of features such as priapism, tinnitus, hearing loss, cerebral accidents and blindness. In the blastic phase, CML leukemic cells resemble acute leukemic cells morphologically. CNS and lymph node involvement are notable in the blastic phase of CML. If untreated, CML patients will progress to the terminal blastic phase in 3 to 5 years.   

!Notes

!Notes

|-

|-

|EXAMPLE t(9;22)(q34;q11.2)||EXAMPLE 3'ABL1 / 5'BCR||EXAMPLE der(22)||EXAMPLE 20% (COSMIC)

|<span class="blue-text">EXAMPLE:</span> t(9;22)(q34;q11.2)||<span class="blue-text">EXAMPLE:</span> 3'ABL1 / 5'BCR||<span class="blue-text">EXAMPLE:</span> der(22)||<span class="blue-text">EXAMPLE:</span> 20% (COSMIC)

EXAMPLE 30% (add reference)

<span class="blue-text">EXAMPLE:</span> 30% (add reference)

|Yes

|Yes

|No

|No

|Yes

|Yes

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

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).

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).

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<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|Content Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition Classification}}

CML is the first cancer that is known to be linked to a specific genetic abnormality, namely the balanced chromosomal translocation known as Philadelphia Chromosome. A focal gene area of BCR (Breakpoint Cluster Region) from chromosome 22 is fused with another gene ABL (Tyrosine protein kinase ABL) that is located on chromosome 9. The chimeric oncogene BCR-ABL is the central to the pathology of CML because ABL carries a domain that is capable of phosphorylating tyrosine residues, activating a cascade of proteins that control the cell cycle. It was reported that 90% - 95% of the CML in chronic phase shows characteristic t(9;22)(q34;q11.2) reciprocal translocation that results in the Ph chromosome. This balanced translocation leads to the formation of the ''BCR/ABL'' fusion gene on chromosome 22 and a reciprocal ''ABL/BCR'' fusion gene on chromosome 9. Studies has shown that the latter gene ''ABL/BCR'' fusion gene does not seem to have any crucial role in CML and no ABL/BCR protein has been found.

CML is the first cancer that is known to be linked to a specific genetic abnormality, namely the balanced chromosomal translocation known as Philadelphia Chromosome. A focal gene area of BCR (Breakpoint Cluster Region) from chromosome 22 is fused with another gene ABL (Tyrosine protein kinase ABL) that is located on chromosome 9. The chimeric oncogene BCR-ABL is the central to the pathology of CML because ABL carries a domain that is capable of phosphorylating tyrosine residues, activating a cascade of proteins that control the cell cycle. It was reported that 90% - 95% of the CML in chronic phase shows characteristic t(9;22)(q34;q11.2) reciprocal translocation that results in the Ph chromosome. This balanced translocation leads to the formation of the ''BCR/ABL'' fusion gene on chromosome 22 and a reciprocal ''ABL/BCR'' fusion gene on chromosome 9. Studies has shown that the latter gene ''ABL/BCR'' fusion gene does not seem to have any crucial role in CML and no ABL/BCR protein has been found.

<blockquote class='blockedit'>{{Box-round|title=v4:Clinical Significance (Diagnosis, Prognosis and Therapeutic Implications).|Please incorporate this section into the relevant tables found in:

<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|Please incorporate this section into the relevant tables found in:

* Chromosomal Rearrangements (Gene Fusions)

* Chromosomal Rearrangements (Gene Fusions)

* Individual Region Genomic Gain/Loss/LOH

* Individual Region Genomic Gain/Loss/LOH

==Individual Region Genomic Gain / Loss / LOH==

==Individual Region Genomic Gain / Loss / LOH==

Put your text here and fill in the table <span style="color:#0070C0">(''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.'') </span>

Put your text here and fill in the table <span style="color:#0070C0">(''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. Do not delete table.'') </span>

{| class="wikitable sortable"

{| class="wikitable sortable"

!Notes

!Notes

|-

|-

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

7

7

|EXAMPLE Loss

|<span class="blue-text">EXAMPLE:</span> Loss

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

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

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

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

chr7

chr7

|Yes

|Yes

|No

|No

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

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).

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

|<span class="blue-text">EXAMPLE:</span>

8

8

|EXAMPLE Gain

|<span class="blue-text">EXAMPLE:</span> Gain

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

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

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

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

chr8

chr8

|No

|No

|No

|No

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

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

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

|}

|}

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<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|Content Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition Classification}}

Not Applicable.

Not Applicable.

==Characteristic Chromosomal Patterns==

==Characteristic Chromosomal Patterns==

Put your text here <span style="color:#0070C0">(''EXAMPLE PATTERNS: 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'')</span>

Put your text here <span style="color:#0070C0">(''EXAMPLE PATTERNS: 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. Do not delete table.'')</span>

{| class="wikitable sortable"

{| class="wikitable sortable"

!Notes

!Notes

|-

|-

|EXAMPLE

|<span class="blue-text">EXAMPLE:</span>

Co-deletion of 1p and 18q

Co-deletion of 1p and 18q

|No

|No

|No

|No

|EXAMPLE:

|<span class="blue-text">EXAMPLE:</span>

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

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

|}

|}

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<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|Content Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition Classification}}

Atypical chronic myeloid leukemia (aCML) is a subtype of myelodysplastic/myeloproliferative neoplasm that lacks Philadelphia chromosome or rearrangements of PDGFRA, PDGFRB, or FGFR1. This hematological disorder has a considerable overlapping clinicopathological features with CML and CMML. It differs from CML by older median age, lower level of granulocytosis, multilineage dysplasia and lack of basophilia. Up until now, no cytogenetic changes have been associated with aCML. In peripheral blood smear, aCML typically shows granulocytic leukocytosis with striking neutrophil dysplasia (nuclear hyposegmentation and hypogranularity).

Atypical chronic myeloid leukemia (aCML) is a subtype of myelodysplastic/myeloproliferative neoplasm that lacks Philadelphia chromosome or rearrangements of PDGFRA, PDGFRB, or FGFR1. This hematological disorder has a considerable overlapping clinicopathological features with CML and CMML. It differs from CML by older median age, lower level of granulocytosis, multilineage dysplasia and lack of basophilia. Up until now, no cytogenetic changes have been associated with aCML. In peripheral blood smear, aCML typically shows granulocytic leukocytosis with striking neutrophil dysplasia (nuclear hyposegmentation and hypogranularity).

==Gene Mutations (SNV / INDEL)==

==Gene Mutations (SNV / INDEL)==

Put your text here and fill in the table <span style="color:#0070C0">(''Instructions: This table is not meant to be an exhaustive list; please include only genes/alterations that are recurrent and common as well either disease defining and/or clinically significant. Can include references 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.'') </span>

Put your text here and fill in the table <span style="color:#0070C0">(''Instructions: This table is not meant to be an exhaustive list; please include only genes/alterations that are recurrent and common as well as either disease defining and/or clinically significant. Can include references 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. Do not delete table.'') </span>

{| class="wikitable sortable"

{| class="wikitable sortable"

!Notes

!Notes

|-

|-

|EXAMPLE: TP53; Variable LOF mutations

|<span class="blue-text">EXAMPLE:</span> TP53; Variable LOF mutations

EXAMPLE:

<span class="blue-text">EXAMPLE:</span>

EGFR; Exon 20 mutations

EGFR; Exon 20 mutations

EXAMPLE: BRAF; Activating mutations

<span class="blue-text">EXAMPLE:</span> BRAF; Activating mutations

|EXAMPLE: TSG

|<span class="blue-text">EXAMPLE:</span> TSG

|EXAMPLE: 20% (COSMIC)

|<span class="blue-text">EXAMPLE:</span> 20% (COSMIC)

EXAMPLE: 30% (add Reference)

<span class="blue-text">EXAMPLE:</span> 30% (add Reference)

|EXAMPLE: IDH1 R123H

|<span class="blue-text">EXAMPLE:</span> IDH1 R123H

|EXAMPLE: EGFR amplification

|<span class="blue-text">EXAMPLE:</span> EGFR amplification

|

|

|

|

|

|

|EXAMPLE:  Excludes hairy cell leukemia (HCL) (add reference).

|<span class="blue-text">EXAMPLE:</span>  Excludes hairy cell leukemia (HCL) (add reference).

<br />

<br />

|}

|}

<blockquote class='blockedit'>{{Box-round|title=v4:Gene Mutations (SNV/INDEL)|The content below was from the old template. Please incorporate above.}}

<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|Content Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition Classification}}

A few genes were noted to be altered during the transformed stages of CML, namely TP53'', RB1, MYC, CDKN2A, NRAS, KRAS, RUNX1, MECOM, TET2, CBL, ASXL1, IDH1'' and ''IDH2''.

A few genes were noted to be altered during the transformed stages of CML, namely TP53'', RB1, MYC, CDKN2A, NRAS, KRAS, RUNX1, MECOM, TET2, CBL, ASXL1, IDH1'' and ''IDH2''.

==Genes and Main Pathways Involved==

==Genes and Main Pathways Involved==

Put your text here and fill in the table <span style="color:#0070C0">(''Instructions: Can include references in the table.'')</span>

Put your text here and fill in the table <span style="color:#0070C0">(''Instructions: Can include references in the table. Do not delete table.'')</span>

{| class="wikitable sortable"

{| class="wikitable sortable"

|-

|-

!Gene; Genetic Alteration!!Pathway!!Pathophysiologic Outcome

!Gene; Genetic Alteration!!Pathway!!Pathophysiologic Outcome

|-

|-

|EXAMPLE: BRAF and MAP2K1; Activating mutations

|<span class="blue-text">EXAMPLE:</span> BRAF and MAP2K1; Activating mutations

|EXAMPLE: MAPK signaling

|<span class="blue-text">EXAMPLE:</span> MAPK signaling

|EXAMPLE: Increased cell growth and proliferation

|<span class="blue-text">EXAMPLE:</span> Increased cell growth and proliferation

|-

|-

|EXAMPLE: CDKN2A; Inactivating mutations

|<span class="blue-text">EXAMPLE:</span> CDKN2A; Inactivating mutations

|EXAMPLE: Cell cycle regulation

|<span class="blue-text">EXAMPLE:</span> Cell cycle regulation

|EXAMPLE: Unregulated cell division

|<span class="blue-text">EXAMPLE:</span> Unregulated cell division

|-

|-

|EXAMPLE:  KMT2C and ARID1A; Inactivating mutations

|<span class="blue-text">EXAMPLE:</span>  KMT2C and ARID1A; Inactivating mutations

|EXAMPLE:  Histone modification, chromatin remodeling

|<span class="blue-text">EXAMPLE:</span>  Histone modification, chromatin remodeling

|EXAMPLE:  Abnormal gene expression program

|<span class="blue-text">EXAMPLE:</span>  Abnormal gene expression program

|}

|}

<blockquote class='blockedit'>{{Box-round|title=v4:Genes and Main Pathways Involved|The content below was from the old template. Please incorporate above.}}

<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|Content Update To WHO 5th Edition Classification Is In Process; Content Below is Based on WHO 4th Edition Classification}}

[[File:BCR-ABL-ASS1 abnormal double fusions.jpg|thumb|Image courtesy of Fabiola Quintero-Rivera, MD]]

[[File:BCR-ABL-ASS1 abnormal double fusions.jpg|thumb|Image courtesy of Fabiola Quintero-Rivera, MD]]

Breakpoint Cluster Region protein (BCR) is encoded by ''BCR'' gene, located on chromosome 22. BCR protein has serine/threonine kinase activity.<ref name=":0" /> The protein is also a GTPase-activating protein for p21rac and other kinases.<ref>{{Cite journal|title=BCR BCR activator of RhoGEF and GTPase [Homo sapiens (human)] - Gene - NCBI|url=https://www.ncbi.nlm.nih.gov/gene?cmd=Retrieve&dopt=full_report&list_uids=613}}</ref> BCR protein is involved in the two main pathways: FGFR1 mutant receptor activation and G-protein signaling HRAS regulation pathway.<ref>{{Cite journal|last=Mn|first=Peiris|last2=F|first2=Li|last3=Dj|first3=Donoghue|date=2019|title=BCR: A Promiscuous Fusion Partner in Hematopoietic Disorders|url=https://pubmed.ncbi.nlm.nih.gov/31105873/|language=en|doi=10.18632/oncotarget.26837|pmc=PMC6505627|pmid=31105873}}</ref> BCR-associated genetic rearrangement gives rise to hematological disorders. The ''ABL1'' gene is located on chromosome 9q34.12 and encodes for ABL1 protein, which was discovered to be a tyrosine kinase protein.<ref>{{Cite journal|last=B|first=Chereda|last2=Jv|first2=Melo|date=2015|title=Natural Course and Biology of CML|url=https://pubmed.ncbi.nlm.nih.gov/25814077/|language=en|pmid=25814077}}</ref> Depending on the breakpoint of the ''BCR'' gene, the size of the fusion protein can vary:  p190bcr-abl, p210bcr-abl, and p230bcr-abl, leading to three different isoforms.<ref name=":0" /> ''BCR-ABL1'' gene fusion encodes a chimeric protein, which is mostly 210 kDa(P210''BCRABL1'') with constitutive tyrosine-kinase activity, escaping the cytokine regulation and regulatory controls of many intracellular signaling pathways that are associated with proliferation, differentiation and apoptosis.<ref>{{Cite journal|last=Jb|first=Konopka|last2=Sm|first2=Watanabe|last3=On|first3=Witte|date=1984|title=An Alteration of the Human C-Abl Protein in K562 Leukemia Cells Unmasks Associated Tyrosine Kinase Activity|url=https://pubmed.ncbi.nlm.nih.gov/6204766/|language=en|pmid=6204766}}</ref><ref>{{Cite journal|last=R|first=Ren|date=2005|title=Mechanisms of BCR-ABL in the Pathogenesis of Chronic Myelogenous Leukaemia|url=https://pubmed.ncbi.nlm.nih.gov/15719031/|language=en|pmid=15719031}}</ref> Many of the target proteins that are affected by dimerization of constitutive kinase activity of BCR-ABL fusion protein include STAT, RAS, RAF, JUN kinase, MYC, AKT, and other transducers.<ref>{{Cite journal|last=S|first=Faderl|last2=M|first2=Talpaz|last3=Z|first3=Estrov|last4=S|first4=O'Brien|last5=R|first5=Kurzrock|last6=Hm|first6=Kantarjian|date=1999|title=The Biology of Chronic Myeloid Leukemia|url=https://pubmed.ncbi.nlm.nih.gov/10403855/|language=en|pmid=10403855}}</ref><ref>{{Cite journal|last=Cl|first=Sawyers|date=1999|title=Chronic Myeloid Leukemia|url=https://pubmed.ncbi.nlm.nih.gov/10219069/|language=en|pmid=10219069}}</ref> It was shown that when CML progresses to the blastic crisis phase, a new additional mutation is acquired GSK3beta, which leads to the activation of beta-catenin, preventing myeloid cell lineages to mature.<ref>{{Cite journal|last=Ch|first=Jamieson|last2=Le|first2=Ailles|last3=Sj|first3=Dylla|last4=M|first4=Muijtjens|last5=C|first5=Jones|last6=Jl|first6=Zehnder|last7=J|first7=Gotlib|last8=K|first8=Li|last9=Mg|first9=Manz|date=2004|title=Granulocyte-macrophage Progenitors as Candidate Leukemic Stem Cells in Blast-Crisis CML|url=https://pubmed.ncbi.nlm.nih.gov/15306667/|language=en|pmid=15306667}}</ref><ref>{{Cite journal|last=Ae|first=Abrahamsson|last2=I|first2=Geron|last3=J|first3=Gotlib|last4=Kh|first4=Dao|last5=Cf|first5=Barroga|last6=Ig|first6=Newton|last7=Fj|first7=Giles|last8=J|first8=Durocher|last9=Rs|first9=Creusot|date=2009|title=Glycogen Synthase Kinase 3beta Missplicing Contributes to Leukemia Stem Cell Generation|url=https://pubmed.ncbi.nlm.nih.gov/19237556/|language=en|doi=10.1073/pnas.0900189106|pmc=PMC2646624|pmid=19237556}}</ref>

Breakpoint Cluster Region protein (BCR) is encoded by ''BCR'' gene, located on chromosome 22. BCR protein has serine/threonine kinase activity.<ref name=":0" /> The protein is also a GTPase-activating protein for p21rac and other kinases.<ref>{{Cite journal|title=BCR BCR activator of RhoGEF and GTPase [Homo sapiens (human)] - Gene - NCBI|url=https://www.ncbi.nlm.nih.gov/gene?cmd=Retrieve&dopt=full_report&list_uids=613}}</ref> BCR protein is involved in the two main pathways: FGFR1 mutant receptor activation and G-protein signaling HRAS regulation pathway.<ref>{{Cite journal|last=Mn|first=Peiris|last2=F|first2=Li|last3=Dj|first3=Donoghue|date=2019|title=BCR: A Promiscuous Fusion Partner in Hematopoietic Disorders|url=https://pubmed.ncbi.nlm.nih.gov/31105873/|language=en|doi=10.18632/oncotarget.26837|pmc=PMC6505627|pmid=31105873}}</ref> BCR-associated genetic rearrangement gives rise to hematological disorders. The ''ABL1'' gene is located on chromosome 9q34.12 and encodes for ABL1 protein, which was discovered to be a tyrosine kinase protein.<ref>{{Cite journal|last=B|first=Chereda|last2=Jv|first2=Melo|date=2015|title=Natural Course and Biology of CML|url=https://pubmed.ncbi.nlm.nih.gov/25814077/|language=en|pmid=25814077}}</ref> Depending on the breakpoint of the ''BCR'' gene, the size of the fusion protein can vary:  p190bcr-abl, p210bcr-abl, and p230bcr-abl, leading to three different isoforms.<ref name=":0" /> ''BCR-ABL1'' gene fusion encodes a chimeric protein, which is mostly 210 kDa(P210''BCRABL1'') with constitutive tyrosine-kinase activity, escaping the cytokine regulation and regulatory controls of many intracellular signaling pathways that are associated with proliferation, differentiation and apoptosis.<ref>{{Cite journal|last=Jb|first=Konopka|last2=Sm|first2=Watanabe|last3=On|first3=Witte|date=1984|title=An Alteration of the Human C-Abl Protein in K562 Leukemia Cells Unmasks Associated Tyrosine Kinase Activity|url=https://pubmed.ncbi.nlm.nih.gov/6204766/|language=en|pmid=6204766}}</ref><ref>{{Cite journal|last=R|first=Ren|date=2005|title=Mechanisms of BCR-ABL in the Pathogenesis of Chronic Myelogenous Leukaemia|url=https://pubmed.ncbi.nlm.nih.gov/15719031/|language=en|pmid=15719031}}</ref> Many of the target proteins that are affected by dimerization of constitutive kinase activity of BCR-ABL fusion protein include STAT, RAS, RAF, JUN kinase, MYC, AKT, and other transducers.<ref>{{Cite journal|last=S|first=Faderl|last2=M|first2=Talpaz|last3=Z|first3=Estrov|last4=S|first4=O'Brien|last5=R|first5=Kurzrock|last6=Hm|first6=Kantarjian|date=1999|title=The Biology of Chronic Myeloid Leukemia|url=https://pubmed.ncbi.nlm.nih.gov/10403855/|language=en|pmid=10403855}}</ref><ref>{{Cite journal|last=Cl|first=Sawyers|date=1999|title=Chronic Myeloid Leukemia|url=https://pubmed.ncbi.nlm.nih.gov/10219069/|language=en|pmid=10219069}}</ref> It was shown that when CML progresses to the blastic crisis phase, a new additional mutation is acquired GSK3beta, which leads to the activation of beta-catenin, preventing myeloid cell lineages to mature.<ref>{{Cite journal|last=Ch|first=Jamieson|last2=Le|first2=Ailles|last3=Sj|first3=Dylla|last4=M|first4=Muijtjens|last5=C|first5=Jones|last6=Jl|first6=Zehnder|last7=J|first7=Gotlib|last8=K|first8=Li|last9=Mg|first9=Manz|date=2004|title=Granulocyte-macrophage Progenitors as Candidate Leukemic Stem Cells in Blast-Crisis CML|url=https://pubmed.ncbi.nlm.nih.gov/15306667/|language=en|pmid=15306667}}</ref><ref>{{Cite journal|last=Ae|first=Abrahamsson|last2=I|first2=Geron|last3=J|first3=Gotlib|last4=Kh|first4=Dao|last5=Cf|first5=Barroga|last6=Ig|first6=Newton|last7=Fj|first7=Giles|last8=J|first8=Durocher|last9=Rs|first9=Creusot|date=2009|title=Glycogen Synthase Kinase 3beta Missplicing Contributes to Leukemia Stem Cell Generation|url=https://pubmed.ncbi.nlm.nih.gov/19237556/|language=en|doi=10.1073/pnas.0900189106|pmc=PMC2646624|pmid=19237556}}</ref>