Changes

==Definition / Description of Disease==

==Definition / Description of Disease==

This is a distinct entity in the 2016 World Health Organization (WHO) classification system<ref name=":1">Campo E, et al., (2017). Chronic lymphocytic leukemia/small lymphocytic lymphoma, 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, p216-221.</ref>. Chronic Lymphocytic Leukemia (CLL) is a chronic lymphoproliferative disorder characterized by monoclonal B cell proliferation. CLL is defined by the presence of >5x10⁹/L monoclonal B-cells in the peripheral blood. Cells are small, mature appearing lymphocytes with light chain restriction by flow cytometry. The term small lymphocytic lymphoma (SLL) is used for cases with <5x10⁹/L circulating monoclonal B-cells and documented nodal, splenic, or other extramedullary involvement<ref name=":2">{{Cite journal|last=Hallek|first=Michael|last2=Cheson|first2=Bruce D.|last3=Catovsky|first3=Daniel|last4=Caligaris-Cappio|first4=Federico|last5=Dighiero|first5=Guillaume|last6=Döhner|first6=Hartmut|last7=Hillmen|first7=Peter|last8=Keating|first8=Michael J.|last9=Montserrat|first9=Emili|date=2008-06-15|title=Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the International Workshop on Chronic Lymphocytic Leukemia updating the National Cancer Institute-Working Group 1996 guidelines|url=https://pubmed.ncbi.nlm.nih.gov/18216293|journal=Blood|volume=111|issue=12|pages=5446–5456|doi=10.1182/blood-2007-06-093906|issn=1528-0020|pmc=2972576|pmid=18216293}}</ref>.       

This is a distinct entity in the [https://tumourclassification.iarc.who.int/welcome/ 5th edition World Health Organization (WHO) classification system].  It was also a distinct entity in the 2016 WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues revised 4th edition<ref name=":1">Campo E, et al., (2017). Chronic lymphocytic leukemia/small lymphocytic lymphoma, 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, p216-221.</ref>. Chronic Lymphocytic Leukemia (CLL) is a chronic lymphoproliferative disorder characterized by monoclonal B cell proliferation. CLL is defined by the presence of >5x10⁹/L monoclonal B-cells in the peripheral blood. Cells are small, mature appearing lymphocytes with light chain restriction by flow cytometry. The term small lymphocytic lymphoma (SLL) is used for cases with <5x10⁹/L circulating monoclonal B-cells and documented nodal, splenic, or other extramedullary involvement<ref name=":2">{{Cite journal|last=Hallek|first=Michael|last2=Cheson|first2=Bruce D.|last3=Catovsky|first3=Daniel|last4=Caligaris-Cappio|first4=Federico|last5=Dighiero|first5=Guillaume|last6=Döhner|first6=Hartmut|last7=Hillmen|first7=Peter|last8=Keating|first8=Michael J.|last9=Montserrat|first9=Emili|date=2008-06-15|title=Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the International Workshop on Chronic Lymphocytic Leukemia updating the National Cancer Institute-Working Group 1996 guidelines|url=https://pubmed.ncbi.nlm.nih.gov/18216293|journal=Blood|volume=111|issue=12|pages=5446–5456|doi=10.1182/blood-2007-06-093906|issn=1528-0020|pmc=2972576|pmid=18216293}}</ref>.       

==Synonyms / Terminology==

==Synonyms / Terminology==

*Approximately 80% of CLL patients have a cytogenetic abnormality detectable by fluorescence ''in situ'' hybridization (FISH)

*Approximately 80% of CLL patients have a cytogenetic abnormality detectable by fluorescence ''in situ'' hybridization (FISH)

*Deletion of chromosome 13q14 detected by FISH is the most common cytogenetic abnormality in CLL. The deleted region includes two microRNAs, miR15A and miR16-1<ref name=":4">{{Cite journal|last=Liew|first=Danny|last2=Krum|first2=Henry|date=2002-10|title=The role of aldosterone receptor blockade in the management of cardiovascular disease|url=https://pubmed.ncbi.nlm.nih.gov/12431020|journal=Current Opinion in Investigational Drugs (London, England: 2000)|volume=3|issue=10|pages=1468–1473|issn=1472-4472|pmid=12431020}}</ref>. These microRNAs inhibit the expression of genes involved in apoptosis and cell cycle regulation. Deletion of miR15A and miR16-1 leads to upregulation of BCL2<ref>{{Cite journal|last=Cimmino|first=Amelia|last2=Calin|first2=George Adrian|last3=Fabbri|first3=Muller|last4=Iorio|first4=Marilena V.|last5=Ferracin|first5=Manuela|last6=Shimizu|first6=Masayoshi|last7=Wojcik|first7=Sylwia E.|last8=Aqeilan|first8=Rami I.|last9=Zupo|first9=Simona|date=2005-09-27|title=miR-15 and miR-16 induce apoptosis by targeting BCL2|url=https://pubmed.ncbi.nlm.nih.gov/16166262|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=102|issue=39|pages=13944–13949|doi=10.1073/pnas.0506654102|issn=0027-8424|pmc=1236577|pmid=16166262}}</ref>. Deletion of 13q14 as the sole cytogenetic abnormality is associated with a favorable prognosis. Deletions may be heterozygous or homozygous with a similar prognosis. Individuals with a high percentage of nuclei with 13q deletion (>65%) may have a less favorable prognosis<ref>{{Cite journal|last=Van Dyke|first=Daniel L.|last2=Shanafelt|first2=Tait D.|last3=Call|first3=Timothy G.|last4=Zent|first4=Clive S.|last5=Smoley|first5=Stephanie A.|last6=Rabe|first6=Kari G.|last7=Schwager|first7=Susan M.|last8=Sonbert|first8=Jessica C.|last9=Slager|first9=Susan L.|date=2010-02|title=A comprehensive evaluation of the prognostic significance of 13q deletions in patients with B-chronic lymphocytic leukaemia|url=https://pubmed.ncbi.nlm.nih.gov/19895615|journal=British Journal of Haematology|volume=148|issue=4|pages=544–550|doi=10.1111/j.1365-2141.2009.07982.x|issn=1365-2141|pmc=2866061|pmid=19895615}}</ref>

*Deletion of chromosome 13q14 detected by FISH is the most common cytogenetic abnormality in CLL. The deleted region includes two microRNAs, ''miR15A'' and ''miR16-1''<ref name=":4">{{Cite journal|last=Liew|first=Danny|last2=Krum|first2=Henry|date=2002-10|title=The role of aldosterone receptor blockade in the management of cardiovascular disease|url=https://pubmed.ncbi.nlm.nih.gov/12431020|journal=Current Opinion in Investigational Drugs (London, England: 2000)|volume=3|issue=10|pages=1468–1473|issn=1472-4472|pmid=12431020}}</ref>. These microRNAs inhibit the expression of genes involved in apoptosis and cell cycle regulation. Deletion of miR15A and miR16-1 leads to upregulation of BCL2<ref>{{Cite journal|last=Cimmino|first=Amelia|last2=Calin|first2=George Adrian|last3=Fabbri|first3=Muller|last4=Iorio|first4=Marilena V.|last5=Ferracin|first5=Manuela|last6=Shimizu|first6=Masayoshi|last7=Wojcik|first7=Sylwia E.|last8=Aqeilan|first8=Rami I.|last9=Zupo|first9=Simona|date=2005-09-27|title=miR-15 and miR-16 induce apoptosis by targeting BCL2|url=https://pubmed.ncbi.nlm.nih.gov/16166262|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=102|issue=39|pages=13944–13949|doi=10.1073/pnas.0506654102|issn=0027-8424|pmc=1236577|pmid=16166262}}</ref>. Deletion of 13q14 as the sole cytogenetic abnormality is associated with a favorable prognosis. Deletions may be heterozygous or homozygous with a similar prognosis. Individuals with a high percentage of nuclei with 13q deletion (>65%) may have a less favorable prognosis<ref>{{Cite journal|last=Van Dyke|first=Daniel L.|last2=Shanafelt|first2=Tait D.|last3=Call|first3=Timothy G.|last4=Zent|first4=Clive S.|last5=Smoley|first5=Stephanie A.|last6=Rabe|first6=Kari G.|last7=Schwager|first7=Susan M.|last8=Sonbert|first8=Jessica C.|last9=Slager|first9=Susan L.|date=2010-02|title=A comprehensive evaluation of the prognostic significance of 13q deletions in patients with B-chronic lymphocytic leukaemia|url=https://pubmed.ncbi.nlm.nih.gov/19895615|journal=British Journal of Haematology|volume=148|issue=4|pages=544–550|doi=10.1111/j.1365-2141.2009.07982.x|issn=1365-2141|pmc=2866061|pmid=19895615}}</ref>

*Deletion of 17p, which includes ''TP53'', is associated with poor prognosis and resistance to standard chemotherapy regimens<ref name=":5">{{Cite journal|last=Döhner|first=H.|last2=Stilgenbauer|first2=S.|last3=Benner|first3=A.|last4=Leupolt|first4=E.|last5=Kröber|first5=A.|last6=Bullinger|first6=L.|last7=Döhner|first7=K.|last8=Bentz|first8=M.|last9=Lichter|first9=P.|date=2000-12-28|title=Genomic aberrations and survival in chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/11136261|journal=The New England Journal of Medicine|volume=343|issue=26|pages=1910–1916|doi=10.1056/NEJM200012283432602|issn=0028-4793|pmid=11136261}}</ref>.

*Deletion of 17p, which includes ''TP53'', is associated with poor prognosis and resistance to standard chemotherapy regimens<ref name=":5">{{Cite journal|last=Döhner|first=H.|last2=Stilgenbauer|first2=S.|last3=Benner|first3=A.|last4=Leupolt|first4=E.|last5=Kröber|first5=A.|last6=Bullinger|first6=L.|last7=Döhner|first7=K.|last8=Bentz|first8=M.|last9=Lichter|first9=P.|date=2000-12-28|title=Genomic aberrations and survival in chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/11136261|journal=The New England Journal of Medicine|volume=343|issue=26|pages=1910–1916|doi=10.1056/NEJM200012283432602|issn=0028-4793|pmid=11136261}}</ref>.

|Yes

|Yes

|No

|No

|Can also be detected in the homozygous state. Biallelic deletions are often cryptic and not cytogenetically visible<ref>{{Cite journal|last=Migliazza|first=A.|last2=Bosch|first2=F.|last3=Komatsu|first3=H.|last4=Cayanis|first4=E.|last5=Martinotti|first5=S.|last6=Toniato|first6=E.|last7=Guccione|first7=E.|last8=Qu|first8=X.|last9=Chien|first9=M.|date=2001-04-01|title=Nucleotide sequence, transcription map, and mutation analysis of the 13q14 chromosomal region deleted in B-cell chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/11264177|journal=Blood|volume=97|issue=7|pages=2098–2104|doi=10.1182/blood.v97.7.2098|issn=0006-4971|pmid=11264177}}</ref>. 13q deletion as the sole abnormality is typically associated with a good prognosis, however, CLL with a high percentage of nuclei with 13q deletion may have a more aggressive clinical course<ref>{{Cite journal|last=Dal Bo|first=Michele|last2=Rossi|first2=Francesca Maria|last3=Rossi|first3=Davide|last4=Deambrogi|first4=Clara|last5=Bertoni|first5=Francesco|last6=Del Giudice|first6=Ilaria|last7=Palumbo|first7=Giuseppe|last8=Nanni|first8=Mauro|last9=Rinaldi|first9=Andrea|date=2011-08|title=13q14 deletion size and number of deleted cells both influence prognosis in chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/21563234|journal=Genes, Chromosomes & Cancer|volume=50|issue=8|pages=633–643|doi=10.1002/gcc.20885|issn=1098-2264|pmid=21563234}}</ref>

|Can also be detected in the homozygous state. Biallelic deletions are often cryptic and not cytogenetically visible<ref>{{Cite journal|last=Migliazza|first=A.|last2=Bosch|first2=F.|last3=Komatsu|first3=H.|last4=Cayanis|first4=E.|last5=Martinotti|first5=S.|last6=Toniato|first6=E.|last7=Guccione|first7=E.|last8=Qu|first8=X.|last9=Chien|first9=M.|date=2001-04-01|title=Nucleotide sequence, transcription map, and mutation analysis of the 13q14 chromosomal region deleted in B-cell chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/11264177|journal=Blood|volume=97|issue=7|pages=2098–2104|doi=10.1182/blood.v97.7.2098|issn=0006-4971|pmid=11264177}}</ref>. 13q deletion as the sole abnormality is typically associated with a good prognosis, however, CLL with a high percentage of nuclei with 13q deletion may have a more aggressive clinical course<ref>{{Cite journal|last=Dal Bo|first=Michele|last2=Rossi|first2=Francesca Maria|last3=Rossi|first3=Davide|last4=Deambrogi|first4=Clara|last5=Bertoni|first5=Francesco|last6=Del Giudice|first6=Ilaria|last7=Palumbo|first7=Giuseppe|last8=Nanni|first8=Mauro|last9=Rinaldi|first9=Andrea|date=2011-08|title=13q14 deletion size and number of deleted cells both influence prognosis in chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/21563234|journal=Genes, Chromosomes & Cancer|volume=50|issue=8|pages=633–643|doi=10.1002/gcc.20885|issn=1098-2264|pmid=21563234}}</ref>

|-

|-

|11q22.3 deletion

|11q22.3 deletion

|Unknown

|Unknown

|No

|No

|Conflicting evidence on prognostic significance. As a sole abnormality may be associated with low risk. Associated with intermediate risk if NOTCH1 mutation is present<ref name=":8" />

|Conflicting evidence on prognostic significance. As a sole abnormality may be associated with low risk. Associated with intermediate risk if ''NOTCH1'' mutation is present<ref name=":8" />

|-

|-

|6q21 deletion

|6q21 deletion

*IGHV genes are mutated in 50-70% of cases and unmutated in 30-50%.

*IGHV genes are mutated in 50-70% of cases and unmutated in 30-50%.

*Unmutated IGHV genes have been shown to have a poorer prognosis, along with TP53, BIRC3, NOTCH1, and SF3B1 mutations.

*Unmutated IGHV genes have been shown to have a poorer prognosis, along with ''TP53'', ''BIRC3'', ''NOTCH1'', and ''SF3B1'' mutations.

{| class="wikitable sortable"

{| class="wikitable sortable"

Note: A more extensive list of mutations can be found in cBioportal (https://www.cbioportal.org/), COSMIC (https://cancer.sanger.ac.uk/cosmic), ICGC (https://dcc.icgc.org/) and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

Note: A more extensive list of mutations can be found in cBioportal (https://www.cbioportal.org/), COSMIC (https://cancer.sanger.ac.uk/cosmic), ICGC (https://dcc.icgc.org/) and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

==Epigenomic Alterations==

==Epigenomic Alterations==

Whole genome methylation studies have identified three epigenetic subgroups of CLL<ref name=":10">{{Cite journal|last=Queirós|first=A. C.|last2=Villamor|first2=N.|last3=Clot|first3=G.|last4=Martinez-Trillos|first4=A.|last5=Kulis|first5=M.|last6=Navarro|first6=A.|last7=Penas|first7=E. M. M.|last8=Jayne|first8=S.|last9=Majid|first9=A.|date=2015-03|title=A B-cell epigenetic signature defines three biologic subgroups of chronic lymphocytic leukemia with clinical impact|url=https://pubmed.ncbi.nlm.nih.gov/25151957|journal=Leukemia|volume=29|issue=3|pages=598–605|doi=10.1038/leu.2014.252|issn=1476-5551|pmid=25151957}}</ref> [PMID: 25151957]. These subgroups are related to different stages of B-cell maturation and include naïve B-cell like, intermediate, and memory B-cell like CLL. Naïve B-cell like epigenetic subgroup mainly has unmutated IGHV, whereas the memory B-like subgroup mainly have mutated IGHV genes. The intermediate epigenetic subgroup was also found to have mainly mutated IGHV, however, is associated with a worse prognosis than the memory B-like subgroup. The epigenetic classification was found to be an independent prognostic factor for time to first treatment<ref name=":10" /><ref>{{Cite journal|last=Oakes|first=Christopher C.|last2=Seifert|first2=Marc|last3=Assenov|first3=Yassen|last4=Gu|first4=Lei|last5=Przekopowitz|first5=Martina|last6=Ruppert|first6=Amy S.|last7=Wang|first7=Qi|last8=Imbusch|first8=Charles D.|last9=Serva|first9=Andrius|date=2016-03|title=DNA methylation dynamics during B cell maturation underlie a continuum of disease phenotypes in chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/26780610|journal=Nature Genetics|volume=48|issue=3|pages=253–264|doi=10.1038/ng.3488|issn=1546-1718|pmc=4963005|pmid=26780610}}</ref>.

Whole genome methylation studies have identified three epigenetic subgroups of CLL<ref name=":10">{{Cite journal|last=Queirós|first=A. C.|last2=Villamor|first2=N.|last3=Clot|first3=G.|last4=Martinez-Trillos|first4=A.|last5=Kulis|first5=M.|last6=Navarro|first6=A.|last7=Penas|first7=E. M. M.|last8=Jayne|first8=S.|last9=Majid|first9=A.|date=2015-03|title=A B-cell epigenetic signature defines three biologic subgroups of chronic lymphocytic leukemia with clinical impact|url=https://pubmed.ncbi.nlm.nih.gov/25151957|journal=Leukemia|volume=29|issue=3|pages=598–605|doi=10.1038/leu.2014.252|issn=1476-5551|pmid=25151957}}</ref>. These subgroups are related to different stages of B-cell maturation and include naïve B-cell like, intermediate, and memory B-cell like CLL. Naïve B-cell like epigenetic subgroup mainly has unmutated IGHV, whereas the memory B-like subgroup mainly have mutated IGHV genes. The intermediate epigenetic subgroup was also found to have mainly mutated IGHV, however, is associated with a worse prognosis than the memory B-like subgroup. The epigenetic classification was found to be an independent prognostic factor for time to first treatment<ref name=":10" /><ref>{{Cite journal|last=Oakes|first=Christopher C.|last2=Seifert|first2=Marc|last3=Assenov|first3=Yassen|last4=Gu|first4=Lei|last5=Przekopowitz|first5=Martina|last6=Ruppert|first6=Amy S.|last7=Wang|first7=Qi|last8=Imbusch|first8=Charles D.|last9=Serva|first9=Andrius|date=2016-03|title=DNA methylation dynamics during B cell maturation underlie a continuum of disease phenotypes in chronic lymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/26780610|journal=Nature Genetics|volume=48|issue=3|pages=253–264|doi=10.1038/ng.3488|issn=1546-1718|pmc=4963005|pmid=26780610}}</ref>.

==Genes and Main Pathways Involved==

==Genes and Main Pathways Involved==