HAEM5:T-prolymphocytic leukaemia: Difference between revisions
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|Negative (subset)||CD8 (in some cases CD4+/CD8+ or CD4-/CD8+) | |Negative (subset)||CD8 (in some cases CD4+/CD8+ or CD4-/CD8+) | ||
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== | ==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> | |||
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|WHO Essential Criteria (Genetics)* | |||
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|WHO Desirable Criteria (Genetics)* | |||
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|Other Classification | |||
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<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> | |||
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|Acceptable | |||
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|Not Recommended | |||
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==Gene Rearrangements== | |||
Rearrangements involving the TCL1 (T-cell leukemia/lymphoma 1) family genes—''TCL1A, MTCP1'' (mature T-cell proliferation), or ''TCL1B'' (also known as ''TCL1/MTCP''1-like 1 [''TML''1])—are highly specific to T-PLL and occur in more than 90% of cases. These translocations juxtapose the ''TRA'' locus with the oncogenes ''TCL1A'' or ''TCL1B'', or in the case of t(X;14), with the ''MTCP1'' gene.<ref name=":6" /><ref name=":7" /> | Rearrangements involving the TCL1 (T-cell leukemia/lymphoma 1) family genes—''TCL1A, MTCP1'' (mature T-cell proliferation), or ''TCL1B'' (also known as ''TCL1/MTCP''1-like 1 [''TML''1])—are highly specific to T-PLL and occur in more than 90% of cases. These translocations juxtapose the ''TRA'' locus with the oncogenes ''TCL1A'' or ''TCL1B'', or in the case of t(X;14), with the ''MTCP1'' gene.<ref name=":6" /><ref name=":7" /> | ||
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|'''Major diagnostic criteria'''.<ref name=":6" /> | |'''Major diagnostic criteria'''.<ref name=":6" /> | ||
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==Individual Region Genomic Gain / Loss / LOH== | ==Individual Region Genomic Gain/Loss/LOH== | ||
Approximately 70-80% of T-PLL karyotypes are complex, which is considered minor diagnostic criteria, and usually include 3-5 or more structural aberrations. Common cytogenetic abnormalities include those of chromosome 8, such as idic(8)(p11.2), t(8;8)(p11.2;q12), and trisomy 8q. Other frequent changes are deletions in 12p13 and 22q, gains in 8q24 (MYC), and abnormalities in chromosomes 5p, 6, and 17.<ref name=":5" /> | Approximately 70-80% of T-PLL karyotypes are complex, which is considered minor diagnostic criteria, and usually include 3-5 or more structural aberrations. Common cytogenetic abnormalities include those of chromosome 8, such as idic(8)(p11.2), t(8;8)(p11.2;q12), and trisomy 8q. Other frequent changes are deletions in 12p13 and 22q, gains in 8q24 (MYC), and abnormalities in chromosomes 5p, 6, and 17.<ref name=":5" /> | ||
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<nowiki>**</nowiki>Cases lacking these abnormalities may be referred to as "TCL1 family-negative T-PLL." by some investigators<ref name=":0" />. It is, however, recommended in WHO-HAEM5 that such cases should preferably be classified as peripheral T-cell lymphoma NOS with leukemic involvement (after exclusion of other specific leukemic T-cell entities) as there are insufficient clinicopathological and molecular data to determine the relationship of TCL1 family–negative T-PLL to T-PLL. | <nowiki>**</nowiki>Cases lacking these abnormalities may be referred to as "TCL1 family-negative T-PLL." by some investigators<ref name=":0" />. It is, however, recommended in WHO-HAEM5 that such cases should preferably be classified as peripheral T-cell lymphoma NOS with leukemic involvement (after exclusion of other specific leukemic T-cell entities) as there are insufficient clinicopathological and molecular data to determine the relationship of TCL1 family–negative T-PLL to T-PLL. | ||
==Characteristic Chromosomal Patterns== | ==Characteristic Chromosomal or Other Global Mutational Patterns== | ||
[[File:Inv(14)(q11.2q32).png|thumb|Inv(14)(q11.2q32)]] | [[File:Inv(14)(q11.2q32).png|thumb|Inv(14)(q11.2q32)]] | ||
The most common chromosomal abnormality in T-PLL involves an inversion of chromosome 14, with breakpoints at q11.2 and q32.1, observed in about 60-80% of patients and described as inv(14). Additionally, in 10-20% of cases, there is a translocation t(14;14)(q11.2;q32.1).<ref name=":5" /> <ref name=":7" /> | The most common chromosomal abnormality in T-PLL involves an inversion of chromosome 14, with breakpoints at q11.2 and q32.1, observed in about 60-80% of patients and described as inv(14). Additionally, in 10-20% of cases, there is a translocation t(14;14)(q11.2;q32.1).<ref name=":5" /> <ref name=":7" /> | ||
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|The most common chromosomal abnormality in T-PLL involves an inversion of chromosome 14, with breakpoints at q11.2 and q32.1, observed in about 60-80% of patients and described as inv(14). Additionally, in 10-20% of cases, there is a translocation t(14;14)(q11.2;q32.1) | |The most common chromosomal abnormality in T-PLL involves an inversion of chromosome 14, with breakpoints at q11.2 and q32.1, observed in about 60-80% of patients and described as inv(14). Additionally, in 10-20% of cases, there is a translocation t(14;14)(q11.2;q32.1) | ||
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==Gene Mutations (SNV / INDEL)== | ==Gene Mutations (SNV/INDEL)== | ||
Although gene mutations beyond ''TCL1'' family alterations are not yet recognized as diagnostic criteria and remain under investigation for T-PLL, the mutational landscape of T-PLL provides valuable insights. These discoveries open up potential avenues for novel targeted therapies in treating this aggressive form of leukemia. | Although gene mutations beyond ''TCL1'' family alterations are not yet recognized as diagnostic criteria and remain under investigation for T-PLL, the mutational landscape of T-PLL provides valuable insights. These discoveries open up potential avenues for novel targeted therapies in treating this aggressive form of leukemia. | ||