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

Holli M. Drendel, PhD, FACMGG, Carolinas Pathology Group, Charlotte  

==Cancer Category / Type==

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=":0">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>

Put your text here <span style="color:#0070C0">(''Instructions: Include currently used terms and major historical ones, adding “(historical)” after the latter.'') </span>

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=":1">{{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=05 2020|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=":1" />

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|EXAMPLE Asymptomatic (incidental finding on complete blood counts)

 

 

 

|EXAMPLE Cytopenias

 

EXAMPLE Lymphocytosis (low level)

There are no unique morphological or cytochemical features that distinguish this entity from other types of ALL.<ref name=":0" />

No detailed information is known, other than these cases occur exclusively in B-ALL.<ref name=":0" />

|Positive (universal)||EXAMPLE CD1

|Positive (subset)||EXAMPLE CD2

|Negative (universal)||EXAMPLE CD3

|Negative (subset)||EXAMPLE CD4

|t(12;21)(p13.2;q22.1)||''ETV6-RUNX1''||der(21)||

</blockquote>

 

 

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.  

 

Because of the unique nature of the iAMP21 abnormality, cases that present with additional genomic lesions that may suggest another category, such as a CRLF2 rearrangement, should still be classified as B-ALL with iAMP21.

 

 

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>

|EXAMPLE

 

|EXAMPLE Loss

|EXAMPLE

 

|EXAMPLE Gain

|}

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>

|EXAMPLE

 

Co-deletion of 1p and 18q

|Yes

|No

|No

|EXAMPLE:

 

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

<blockquote class='blockedit'>{{Box-round|title=v4:Characteristic Chromosomal Aberrations / Patterns|The content below was from the old template. Please incorporate above.}}

[[File:IAMP21 CMA .png|center|thumb|861x861px|Characteristic iAMP21 CMA; Courtesy of Fullerton Genetics Lab]]

iAMP21 cases have a characteristic pattern that is both complex and variable. This pattern comprises multiple regions of gain, amplification and deletion. Further, it often is accompanied by a terminal deletion of 21q. 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. This is part of the critical region consistently amplified (chr21:32.8-37.9 Mb, GRCh37/hg19). 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=":1" /><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>

 

 

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>

|EXAMPLE: TP53; Variable LOF mutations

 

 

 

|EXAMPLE: 20% (COSMIC)

 

|-

|''NRAS''|| || || ||45%

|-

|''KRAS''

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

|EXAMPLE: BRAF and MAP2K1; Activating mutations

|EXAMPLE: MAPK signaling

Put your text here <span style="color:#0070C0">(''Instructions: Include associated hereditary conditions/syndromes that cause this entity or are caused by this entity.'') </span>