Compendium of Cancer Genome Aberrations

HAEM5:B-lymphoblastic leukaemia/lymphoma with iAMP21: Difference between revisions

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Holli M. Drendel, PhD, FACMGG, Carolinas Pathology Group, Charlotte
Holli M. Drendel, PhD, FACMGG, Carolinas Pathology Group, Charlotte
__TOC__
==WHO Classification of Disease==
==WHO Classification of Disease==


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==Definition / Description of Disease==
==Related Terminology==
 
Intrachromosomal amplification of chromosome 21 (iAMP21) is a neoplasm of lymphoblasts that are of the B-cell lineage. It is characterized by amplification of the ''RUNX1'' gene at 21q22.3 on a structurally abnormal chromosome 21. Amplification is defined as ≥5 copies of ''RUNX1'' detected by FISH or ≥3 copies of ''RUNX1'' on a single abnormal chromosome 21.<ref name=":02">Borowitz MJ, et al., (2017). B-Lymphoblastic leukaemia/lymphoma 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. IARC Press: Lyon, France.</ref>
 
==Synonyms / Terminology==
 
Put your text here
 
==Epidemiology / Prevalence==


iAMP21 is observed most often in the older pediatric group (median age of 9 years, with a range of 2-30 years). It accounts for ~2% of B-ALL cases including ~2% of standard-risk and 3% of high-risk patients. The incidence in adult B-ALL has not been established; however, it appears to be less prevalent than in the pediatric population.<ref name=":0">{{Cite journal|last=Akkari|first=Yassmine M. N.|last2=Bruyere|first2=Helene|last3=Hagelstrom|first3=R. Tanner|last4=Kanagal-Shamanna|first4=Rashmi|last5=Liu|first5=Jie|last6=Luo|first6=Minjie|last7=Mikhail|first7=Fady M.|last8=Pitel|first8=Beth A.|last9=Raca|first9=Gordana|date=2020-05|title=Evidence-based review of genomic aberrations in B-lymphoblastic leukemia/lymphoma: Report from the cancer genomics consortium working group for lymphoblastic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/32302940|journal=Cancer Genetics|volume=243|pages=52–72|doi=10.1016/j.cancergen.2020.03.001|issn=2210-7762|pmid=32302940}}</ref>
Further, patients carrying a rob(15;21)(q10;q10) have an ~2700-fold increased risk of developing iAMP21 ALL compared to the general population. Additionally, patients with a constitutional ring chromosome 21, r(21), may potentially be predisposed to iAMP21 ALL.<ref name=":0" />
==Clinical Features==
~50% of cases are classified as high-risk based on an age of ≥10 years.<ref>{{Cite journal|last=Harrison|first=Christine J.|date=2015-02-26|title=Blood Spotlight on iAMP21 acute lymphoblastic leukemia (ALL), a high-risk pediatric disease|url=https://pubmed.ncbi.nlm.nih.gov/25608562|journal=Blood|volume=125|issue=9|pages=1383–1386|doi=10.1182/blood-2014-08-569228|issn=1528-0020|pmid=25608562}}</ref> Pediatric iAMP21 has been associated with a poor outcome. It displays an increased rate of relapse when treated on standard protocols. Further, the event-free survival and overall survival were significantly worse for individuals with the iAMP21 and standard-risk B-ALL, but not significant in individuals with iAMP21 and high-risk B-ALL.
{| class="wikitable"
|'''Signs and Symptoms'''
|N/A
|-
|'''Laboratory Findings'''
|Low platelet count
Low WBC count (<50,000/μl)
|}
==Sites of Involvement==
Bone Marrow and peripheral blood
==Morphologic Features==
There are no unique morphological or cytochemical features that distinguish this entity from other types of ALL.<ref name=":02" />
Cytogenetic morphology of the abnormal chromosome 21 can vary markedly between patients.<ref>{{Cite journal|last=Harewood|first=L.|last2=Robinson|first2=H.|last3=Harris|first3=R.|last4=Al-Obaidi|first4=M. Jabbar|last5=Jalali|first5=G. R.|last6=Martineau|first6=M.|last7=Moorman|first7=A. V.|last8=Sumption|first8=N.|last9=Richards|first9=S.|date=2003-03|title=Amplification of AML1 on a duplicated chromosome 21 in acute lymphoblastic leukemia: a study of 20 cases|url=https://pubmed.ncbi.nlm.nih.gov/12646943|journal=Leukemia|volume=17|issue=3|pages=547–553|doi=10.1038/sj.leu.2402849|issn=0887-6924|pmid=12646943}}</ref>
<br />
[[File:IAMP21 met.jpg|center|thumb|875x875px|iAMP21 in a ring formation; Courtesy of Fullerton Genetics Lab]]
==Immunophenotype==
No detailed information is known, other than these cases occur exclusively in B-ALL.<ref name=":02" />
{| class="wikitable sortable"
|-
!Finding!!Marker
|-
|Positive (universal)||N/A
|-
|Positive (subset)||N/A
|-
|Negative (universal)||N/A
|-
|Negative (subset)||N/A
|}
==WHO Essential and Desirable Genetic Diagnostic Criteria==
<span style="color:#0070C0">(''Instructions: The table will have the diagnostic criteria from the WHO book <u>autocompleted</u>; remove any <u>non</u>-genetics related criteria. If applicable, add text about other classification'' ''systems that define this entity and specify how the genetics-related criteria differ.'')</span>
{| class="wikitable"
|+
|WHO Essential Criteria (Genetics)*
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|-
|WHO Desirable Criteria (Genetics)*
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|-
|Other Classification
|
|}
<nowiki>*</nowiki>Note: These are only the genetic/genomic criteria. Additional diagnostic criteria can be found in the [https://tumourclassification.iarc.who.int/home <u>WHO Classification of Tumours</u>].
==Related Terminology==
<span style="color:#0070C0">(''Instructions: The table will have the related terminology from the WHO <u>autocompleted</u>.)''</span>
{| class="wikitable"
{| class="wikitable"
|+
|+
|Acceptable
|Acceptable
|
|N/A
|-
|-
|Not Recommended
|Not Recommended
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|N/A
|}
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{| class="wikitable sortable"
{| class="wikitable sortable"
|-
|-
!Chr #!!'''Gain, Loss, Amp, LOH'''!!'''Minimal Region Cytoband and/or Genomic Coordinates [Genome Build; Size]'''!!'''Relevant Gene(s)'''
!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'''
!Diagnostic, Prognostic, and Therapeutic Significance - D, P, T
!'''Established Clinical Significance Per Guidelines - Yes or No (Source)'''
!Established Clinical Significance Per Guidelines - Yes or No (Source)
!'''Clinical Relevance Details/Other Notes'''
!Clinical Relevance Details/Other Notes
|-
|-
|<span class="blue-text">EXAMPLE:</span>
|<span class="blue-text">EXAMPLE:</span>
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Cytogenetic morphology of the abnormal chromosome 21 can vary markedly between patients.<ref name=":3">{{Cite journal|last=Harewood|first=L.|last2=Robinson|first2=H.|last3=Harris|first3=R.|last4=Al-Obaidi|first4=M. Jabbar|last5=Jalali|first5=G. R.|last6=Martineau|first6=M.|last7=Moorman|first7=A. V.|last8=Sumption|first8=N.|last9=Richards|first9=S.|date=2003-03|title=Amplification of AML1 on a duplicated chromosome 21 in acute lymphoblastic leukemia: a study of 20 cases|url=https://pubmed.ncbi.nlm.nih.gov/12646943|journal=Leukemia|volume=17|issue=3|pages=547–553|doi=10.1038/sj.leu.2402849|issn=0887-6924|pmid=12646943}}</ref>
[[File:IAMP21 met.jpg|center|thumb|875x875px|iAMP21 in a ring formation; Courtesy of Fullerton Genetics Lab]]


In ~80% of iAMP21 B-ALL cases, recurrent secondary abnormalities, both chromosomal and molecular, have been documented. Deletions involving particular genes such as; ''IKZF1, CDKN2A/B, PAX5, SH2B3, ETV6'' and ''RB1'' have also been observed.
In ~80% of iAMP21 B-ALL cases, recurrent secondary abnormalities, both chromosomal and molecular, have been documented. Deletions involving particular genes such as; ''IKZF1, CDKN2A/B, PAX5, SH2B3, ETV6'' and ''RB1'' have also been observed.
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==Characteristic Chromosomal or Other Global Mutational Patterns==
==Characteristic Chromosomal or Other Global Mutational Patterns==
Put your text here and fill in the table <span style="color:#0070C0">(I''nstructions: 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.'')</span>
{| class="wikitable sortable"
|-
!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
|-
|<span class="blue-text">EXAMPLE:</span>
Co-deletion of 1p and 18q
|<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).
|<span class="blue-text">EXAMPLE:</span> Common (Oligodendroglioma)
|<span class="blue-text">EXAMPLE:</span> D, P
|
|
|-
|<span class="blue-text">EXAMPLE:</span>
Microsatellite instability - hypermutated
|
|<span class="blue-text">EXAMPLE:</span> Common (Endometrial carcinoma)
|<span class="blue-text">EXAMPLE:</span> P, T
|
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iAMP21 cases have a characteristic pattern that is both complex and variable. This pattern comprises multiple regions of gain, amplification and deletion. Interestingly, ''RUNX1'' amplification is not always intrachromosomal.<ref>{{Cite journal|last=Arber|first=Daniel A.|date=04 2019|title=The 2016 WHO classification of acute myeloid leukemia: What the practicing clinician needs to know|url=https://pubmed.ncbi.nlm.nih.gov/30926096|journal=Seminars in Hematology|volume=56|issue=2|pages=90–95|doi=10.1053/j.seminhematol.2018.08.002|issn=1532-8686|pmid=30926096}}</ref><ref>{{Cite journal|last=Johnson|first=Ryan C.|last2=Weinberg|first2=Olga K.|last3=Cascio|first3=Michael J.|last4=Dahl|first4=Gary V.|last5=Mitton|first5=Bryan A.|last6=Silverman|first6=Lewis B.|last7=Cherry|first7=Athena M.|last8=Arber|first8=Daniel A.|last9=Ohgami|first9=Robert S.|date=2015-07|title=Cytogenetic Variation of B-Lymphoblastic Leukemia With Intrachromosomal Amplification of Chromosome 21 (iAMP21): A Multi-Institutional Series Review|url=https://pubmed.ncbi.nlm.nih.gov/26071468|journal=American Journal of Clinical Pathology|volume=144|issue=1|pages=103–112|doi=10.1309/AJCPLUYF11HQBYRB|issn=1943-7722|pmid=26071468}}</ref> The formation of iAMP21 is considered to be due to breakage-fusion-bridge cycles followed by chromothripsis and other complex structural rearrangements of chromosome 21. Studies, molecular and cytogenetic, have elucidated a common 5.1 Mb region that includes the ''RUNX1'' gene. However, even though ''RUNX1'' is included in the amplified region, there has not yet been any conclusive evidence that ''RUNX1'' is critical in the pathogenesis of disease given that it is not overexpressed in some individuals with this abnormality.<ref name=":0" /><ref>{{Cite journal|last=Rand|first=Vikki|last2=Parker|first2=Helen|last3=Russell|first3=Lisa J.|last4=Schwab|first4=Claire|last5=Ensor|first5=Hannah|last6=Irving|first6=Julie|last7=Jones|first7=Lisa|last8=Masic|first8=Dino|last9=Minto|first9=Lynne|date=2011-06-23|title=Genomic characterization implicates iAMP21 as a likely primary genetic event in childhood B-cell precursor acute lymphoblastic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/21527530|journal=Blood|volume=117|issue=25|pages=6848–6855|doi=10.1182/blood-2011-01-329961|issn=1528-0020|pmid=21527530}}</ref><ref>{{Cite journal|last=Hunger|first=Stephen P.|last2=Lu|first2=Xiaomin|last3=Devidas|first3=Meenakshi|last4=Camitta|first4=Bruce M.|last5=Gaynon|first5=Paul S.|last6=Winick|first6=Naomi J.|last7=Reaman|first7=Gregory H.|last8=Carroll|first8=William L.|date=2012-05-10|title=Improved survival for children and adolescents with acute lymphoblastic leukemia between 1990 and 2005: a report from the children's oncology group|url=https://pubmed.ncbi.nlm.nih.gov/22412151|journal=Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology|volume=30|issue=14|pages=1663–1669|doi=10.1200/JCO.2011.37.8018|issn=1527-7755|pmc=3383113|pmid=22412151}}</ref>
iAMP21 cases have a characteristic pattern that is both complex and variable. This pattern comprises multiple regions of gain, amplification and deletion. Interestingly, ''RUNX1'' amplification is not always intrachromosomal.<ref>{{Cite journal|last=Arber|first=Daniel A.|date=04 2019|title=The 2016 WHO classification of acute myeloid leukemia: What the practicing clinician needs to know|url=https://pubmed.ncbi.nlm.nih.gov/30926096|journal=Seminars in Hematology|volume=56|issue=2|pages=90–95|doi=10.1053/j.seminhematol.2018.08.002|issn=1532-8686|pmid=30926096}}</ref><ref>{{Cite journal|last=Johnson|first=Ryan C.|last2=Weinberg|first2=Olga K.|last3=Cascio|first3=Michael J.|last4=Dahl|first4=Gary V.|last5=Mitton|first5=Bryan A.|last6=Silverman|first6=Lewis B.|last7=Cherry|first7=Athena M.|last8=Arber|first8=Daniel A.|last9=Ohgami|first9=Robert S.|date=2015-07|title=Cytogenetic Variation of B-Lymphoblastic Leukemia With Intrachromosomal Amplification of Chromosome 21 (iAMP21): A Multi-Institutional Series Review|url=https://pubmed.ncbi.nlm.nih.gov/26071468|journal=American Journal of Clinical Pathology|volume=144|issue=1|pages=103–112|doi=10.1309/AJCPLUYF11HQBYRB|issn=1943-7722|pmid=26071468}}</ref> The formation of iAMP21 is considered to be due to breakage-fusion-bridge cycles followed by chromothripsis and other complex structural rearrangements of chromosome 21. Studies, molecular and cytogenetic, have elucidated a common 5.1 Mb region that includes the ''RUNX1'' gene. However, even though ''RUNX1'' is included in the amplified region, there has not yet been any conclusive evidence that ''RUNX1'' is critical in the pathogenesis of disease given that it is not overexpressed in some individuals with this abnormality.<ref name=":0">{{Cite journal|last=Akkari|first=Yassmine M. N.|last2=Bruyere|first2=Helene|last3=Hagelstrom|first3=R. Tanner|last4=Kanagal-Shamanna|first4=Rashmi|last5=Liu|first5=Jie|last6=Luo|first6=Minjie|last7=Mikhail|first7=Fady M.|last8=Pitel|first8=Beth A.|last9=Raca|first9=Gordana|date=2020-05|title=Evidence-based review of genomic aberrations in B-lymphoblastic leukemia/lymphoma: Report from the cancer genomics consortium working group for lymphoblastic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/32302940|journal=Cancer Genetics|volume=243|pages=52–72|doi=10.1016/j.cancergen.2020.03.001|issn=2210-7762|pmid=32302940}}</ref><ref>{{Cite journal|last=Rand|first=Vikki|last2=Parker|first2=Helen|last3=Russell|first3=Lisa J.|last4=Schwab|first4=Claire|last5=Ensor|first5=Hannah|last6=Irving|first6=Julie|last7=Jones|first7=Lisa|last8=Masic|first8=Dino|last9=Minto|first9=Lynne|date=2011-06-23|title=Genomic characterization implicates iAMP21 as a likely primary genetic event in childhood B-cell precursor acute lymphoblastic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/21527530|journal=Blood|volume=117|issue=25|pages=6848–6855|doi=10.1182/blood-2011-01-329961|issn=1528-0020|pmid=21527530}}</ref><ref>{{Cite journal|last=Hunger|first=Stephen P.|last2=Lu|first2=Xiaomin|last3=Devidas|first3=Meenakshi|last4=Camitta|first4=Bruce M.|last5=Gaynon|first5=Paul S.|last6=Winick|first6=Naomi J.|last7=Reaman|first7=Gregory H.|last8=Carroll|first8=William L.|date=2012-05-10|title=Improved survival for children and adolescents with acute lymphoblastic leukemia between 1990 and 2005: a report from the children's oncology group|url=https://pubmed.ncbi.nlm.nih.gov/22412151|journal=Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology|volume=30|issue=14|pages=1663–1669|doi=10.1200/JCO.2011.37.8018|issn=1527-7755|pmc=3383113|pmid=22412151}}</ref>


{| class="wikitable sortable"
{| class="wikitable sortable"
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[[File:IAMP21 CMA .png|center|thumb|1028x1028px|Characteristic iAMP21 CMA; Courtesy of Fullerton Genetics Lab]]
[[File:IAMP21 CMA .png|center|thumb|1028x1028px|Characteristic iAMP21 CMA; Courtesy of Fullerton Genetics Lab]]
<br />
<br />
==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 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.'') </span>
{| class="wikitable sortable"
|-
!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
|-
|<span class="blue-text">EXAMPLE:</span>''EGFR''
<br />
|<span class="blue-text">EXAMPLE:</span> Exon 18-21 activating mutations
|<span class="blue-text">EXAMPLE:</span> Oncogene
|<span class="blue-text">EXAMPLE:</span> Common (lung cancer)
|<span class="blue-text">EXAMPLE:</span> T
|<span class="blue-text">EXAMPLE:</span> Yes (NCCN)
|<span class="blue-text">EXAMPLE:</span> 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).
|-
|<span class="blue-text">EXAMPLE:</span> ''TP53''; Variable LOF mutations
<br />
|<span class="blue-text">EXAMPLE:</span> Variable LOF mutations
|<span class="blue-text">EXAMPLE:</span> Tumor Supressor Gene
|<span class="blue-text">EXAMPLE:</span> Common (breast cancer)
|<span class="blue-text">EXAMPLE:</span> P
|
|<span class="blue-text">EXAMPLE:</span> >90% are somatic; rare germline alterations associated with Li-Fraumeni syndrome (add reference). Denotes a poor prognosis in breast cancer.
|-
|<span class="blue-text">EXAMPLE:</span> ''BRAF''; Activating mutations
|<span class="blue-text">EXAMPLE:</span> Activating mutations
|<span class="blue-text">EXAMPLE:</span> Oncogene
|<span class="blue-text">EXAMPLE:</span> Common (melanoma)
|<span class="blue-text">EXAMPLE:</span> T
|
|
|-
|
|
|
|
|
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|
|}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.


In a 2016 paper, it was shown that in the iAMP21-ALL exome, the mutations were more commonly transitions (for example: C>T) than transversions or indels.<ref name=":0" /><ref name=":2">{{Cite journal|last=Ryan|first=S. L.|last2=Matheson|first2=E.|last3=Grossmann|first3=V.|last4=Sinclair|first4=P.|last5=Bashton|first5=M.|last6=Schwab|first6=C.|last7=Towers|first7=W.|last8=Partington|first8=M.|last9=Elliott|first9=A.|date=09 2016|title=The role of the RAS pathway in iAMP21-ALL|url=https://pubmed.ncbi.nlm.nih.gov/27168466|journal=Leukemia|volume=30|issue=9|pages=1824–1831|doi=10.1038/leu.2016.80|issn=1476-5551|pmc=5017527|pmid=27168466}}</ref> Frequently, mutations in the RAS signaling pathway have been observed. Interestingly, these mutations were observed to coexist in patterns ranging from 2-3 mutated genes to 2-4 mutations in the same gene in one sample. Further, the ''FLT3''-ITD was more prevalent in iAMP21-ALL.<ref name=":2" />
In a 2016 paper, it was shown that in the iAMP21-ALL exome, the mutations were more commonly transitions (for example: C>T) than transversions or indels.<ref name=":0" /><ref name=":2">{{Cite journal|last=Ryan|first=S. L.|last2=Matheson|first2=E.|last3=Grossmann|first3=V.|last4=Sinclair|first4=P.|last5=Bashton|first5=M.|last6=Schwab|first6=C.|last7=Towers|first7=W.|last8=Partington|first8=M.|last9=Elliott|first9=A.|date=09 2016|title=The role of the RAS pathway in iAMP21-ALL|url=https://pubmed.ncbi.nlm.nih.gov/27168466|journal=Leukemia|volume=30|issue=9|pages=1824–1831|doi=10.1038/leu.2016.80|issn=1476-5551|pmc=5017527|pmid=27168466}}</ref> Frequently, mutations in the RAS signaling pathway have been observed. Interestingly, these mutations were observed to coexist in patterns ranging from 2-3 mutated genes to 2-4 mutations in the same gene in one sample. Further, the ''FLT3''-ITD was more prevalent in iAMP21-ALL.<ref name=":2" />
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{| class="wikitable sortable"
{| class="wikitable sortable"
|-
|-
!Gene; Genetic Alteration!!'''Presumed Mechanism (Tumor Suppressor Gene [TSG] / Oncogene / Other)'''!!'''Prevalence (COSMIC /  TCGA / Other)'''!!'''Concomitant Mutations'''!!'''Mutually Exclusive Mutations'''
!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)'''
!Diagnostic Significance (Yes, No or Unknown)
!Prognostic Significance (Yes, No or Unknown)
!Prognostic Significance (Yes, No or Unknown)
!Therapeutic Significance (Yes, No or Unknown)
!Therapeutic Significance (Yes, No or Unknown)
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==Additional Information==
==Additional Information==


N/A
This disease is <u>defined/characterized</u> as detailed below:
 
*Intrachromosomal amplification of chromosome 21 (iAMP21) is a neoplasm of lymphoblasts that are of the B-cell lineage. It is characterized by amplification of the ''RUNX1'' gene at 21q22.3 on a structurally abnormal chromosome 21. Amplification is defined as ≥5 copies of ''RUNX1'' detected by FISH or ≥3 copies of ''RUNX1'' on a single abnormal chromosome 21.<ref name=":02">Borowitz MJ, et al., (2017). B-Lymphoblastic leukaemia/lymphoma 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. IARC Press: Lyon, France.</ref>
 
The <u>epidemiology/prevalence</u> of this disease is detailed below:
 
*iAMP21 is observed most often in the older pediatric group (median age of 9 years, with a range of 2-30 years). It accounts for ~2% of B-ALL cases including ~2% of standard-risk and 3% of high-risk patients. The incidence in adult B-ALL has not been established; however, it appears to be less prevalent than in the pediatric population.<ref name=":0" />
*Further, patients carrying a rob(15;21)(q10;q10) have an ~2700-fold increased risk of developing iAMP21 ALL compared to the general population. Additionally, patients with a constitutional ring chromosome 21, r(21), may potentially be predisposed to iAMP21 ALL.<ref name=":0" />
 
The <u>clinical features</u> of this disease are detailed below:
 
*~50% of cases are classified as high-risk based on an age of ≥10 years.<ref name=":1">{{Cite journal|last=Harrison|first=Christine J.|date=2015-02-26|title=Blood Spotlight on iAMP21 acute lymphoblastic leukemia (ALL), a high-risk pediatric disease|url=https://pubmed.ncbi.nlm.nih.gov/25608562|journal=Blood|volume=125|issue=9|pages=1383–1386|doi=10.1182/blood-2014-08-569228|issn=1528-0020|pmid=25608562}}</ref> Pediatric iAMP21 has been associated with a poor outcome. It displays an increased rate of relapse when treated on standard protocols. Further, the event-free survival and overall survival were significantly worse for individuals with the iAMP21 and standard-risk B-ALL, but not significant in individuals with iAMP21 and high-risk B-ALL.
*Laboratory findings - Low platelet count; Low WBC count (<50,000/μl)
 
The <u>sites of involvement</u> of this disease are detailed below:
 
*Bone Marrow and peripheral blood
 
The <u>morphologic features</u> of this disease are detailed below:
 
*There are no unique morphological or cytochemical features that distinguish this entity from other types of ALL.<ref name=":02" />
 
The <u>immunophenotype</u> of this disease is detailed below:
 
*No detailed information is known, other than these cases occur exclusively in B-ALL.<ref name=":02" />


==Links==
==Links==
Retrieved from "https://test.ccga.io/index.php/HAEM5:B-lymphoblastic_leukaemia/lymphoma_with_iAMP21"