HAEM5:B-lymphoblastic leukaemia/lymphoma with iAMP21: Difference between revisions
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Cytogenetic morphology of the abnormal chromosome 21 can vary markedly between patients.<ref name=":1">{{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> | Cytogenetic morphology of the abnormal chromosome 21 can vary markedly between patients.<ref name=":1">{{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> | ||
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==Immunophenotype== | ==Immunophenotype== | ||
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Cytogenetic morphology of the abnormal chromosome 21 can vary markedly between patients.<ref name=":1" />[[File:IAMP21 met.jpg|center|thumb|778.994x778.994px|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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This disease is <u>defined/characterized</u> as detailed below: | 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" /> | *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" /> | ||
The <u>epidemiology/prevalence</u> of this disease is detailed below: | 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" /> | *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" /> | *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: | The <u>clinical features</u> of this disease are detailed below: | ||
* Signs and symptoms - ~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. | *Signs and symptoms - ~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. | ||
* Laboratory findings - Low platelet count; Low WBC count (<50,000/μl) | *Laboratory findings - Low platelet count; Low WBC count (<50,000/μl) | ||
The <u>sites of involvement</u> of this disease are detailed below: | The <u>sites of involvement</u> of this disease are detailed below: | ||
* Bone Marrow and peripheral blood | *Bone Marrow and peripheral blood | ||
The <u>morphologic features</u> of this disease are detailed below: | 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 | *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: | 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" /> | *No detailed information is known, other than these cases occur exclusively in B-ALL.<ref name=":02" /> | ||
==Links== | ==Links== | ||