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==Definition / Description of Disease==
 
==Definition / Description of Disease==
T-prolymphocytic leukemia (T-PLL) is an aggressive form of T-cell leukemia marked by the proliferation of small to medium-sized prolymphocytes exhibiting a mature post-thymic T-cell phenotype. This condition is characterized by the juxtaposition of TCL1A or MTCP1 genes to a TR locus, typically the TRA/TRD locus.<ref name=":5">Elenitoba-Johnson K, et al. T-prolymphocytic leukemia. In: WHO Classification of Tumours Editorial Board. Haematolymphoid tumours [Internet]. Lyon (France): International Agency for Research on Cancer; 2024 [cited 2024 June 12]. (WHO classification of tumors series, 5th ed.; vol. 11). Available from: https://tumourclassification.iarc.who.int/chaptercontent/63/209</ref>  
+
T-prolymphocytic leukemia (T-PLL) is an aggressive form of T-cell leukemia marked by the proliferation of small to medium-sized prolymphocytes exhibiting a mature post-thymic T-cell phenotype.<ref name=":5">Elenitoba-Johnson K, et al. T-prolymphocytic leukemia. In: WHO Classification of Tumours Editorial Board. Haematolymphoid tumours [Internet]. Lyon (France): International Agency for Research on Cancer; 2024 [cited 2024 June 12]. (WHO classification of tumors series, 5th ed.; vol. 11). Available from: https://tumourclassification.iarc.who.int/chaptercontent/63/209</ref>  
 
==Synonyms / Terminology==
 
==Synonyms / Terminology==
 
T-cell chronic lymphocytic leukemia
 
T-cell chronic lymphocytic leukemia
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Malignant effusions (15%)
 
Malignant effusions (15%)
  −
Asymptomatic and indolent phase (30% of cases)
   
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|'''Laboratory Findings'''
 
|'''Laboratory Findings'''
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Peripheral blood, bone marrow, spleen (mostly red pulp), liver, lymph node (mostly paracortical), and sometimes skin and serosa (primarily pleura). Extra lymphatic and extramedullary atypical manifestations including skin, muscles and intestines are particularly common in relapse.<ref name=":5" />
 
Peripheral blood, bone marrow, spleen (mostly red pulp), liver, lymph node (mostly paracortical), and sometimes skin and serosa (primarily pleura). Extra lymphatic and extramedullary atypical manifestations including skin, muscles and intestines are particularly common in relapse.<ref name=":5" />
 
==Morphologic Features==
 
==Morphologic Features==
Blood smears in T-PLL typically reveal anemia, thrombocytopenia, and leukocytosis, with atypical lymphocytes in three morphological forms. The most common form (75% of cases) features medium-sized cells with a high nuclear-to-cytoplasmic ratio, moderately condensed chromatin, a single visible nucleolus, and slightly basophilic cytoplasm. In 20% of cases, the cells appear as a small cell variant with densely condensed chromatin and an inconspicuous nucleolus. About 5% of cases exhibit a cerebriform variant with irregular nuclei resembling those in mycosis fungoides. Regardless of the nuclear features, a common morphological characteristic is the presence of cytoplasmic protrusions or blebs.<ref>{{Cite journal|last=Gutierrez|first=Marc|last2=Bladek|first2=Patrick|last3=Goksu|first3=Busra|last4=Murga-Zamalloa|first4=Carlos|last5=Bixby|first5=Dale|last6=Wilcox|first6=Ryan|date=2023-07-28|title=T-Cell Prolymphocytic Leukemia: Diagnosis, Pathogenesis, and Treatment|url=https://pubmed.ncbi.nlm.nih.gov/37569479|journal=International Journal of Molecular Sciences|volume=24|issue=15|pages=12106|doi=10.3390/ijms241512106|issn=1422-0067|pmc=PMC10419310|pmid=37569479}}</ref>Bone marrow aspirates show clusters of these neoplastic cells, with a mixed pattern of involvement including diffuse and interstitial, in trephine core biopsy.<ref name=":6" />
+
Blood smears in T-PLL typically reveal anemia, thrombocytopenia, and leukocytosis, with atypical lymphocytes in three morphological forms: The most common form (75% of cases) features medium-sized cells with a high nuclear-to-cytoplasmic ratio, moderately condensed chromatin, a single visible nucleolus, and slightly basophilic cytoplasm. In 20% of cases, the cells appear as a small cell variant with densely condensed chromatin and an inconspicuous nucleolus. About 5% of cases exhibit a cerebriform variant with irregular nuclei resembling those in mycosis fungoides. Regardless of the nuclear features, a common morphological characteristic is the presence of cytoplasmic protrusions or blebs.<ref>{{Cite journal|last=Gutierrez|first=Marc|last2=Bladek|first2=Patrick|last3=Goksu|first3=Busra|last4=Murga-Zamalloa|first4=Carlos|last5=Bixby|first5=Dale|last6=Wilcox|first6=Ryan|date=2023-07-28|title=T-Cell Prolymphocytic Leukemia: Diagnosis, Pathogenesis, and Treatment|url=https://pubmed.ncbi.nlm.nih.gov/37569479|journal=International Journal of Molecular Sciences|volume=24|issue=15|pages=12106|doi=10.3390/ijms241512106|issn=1422-0067|pmc=PMC10419310|pmid=37569479}}</ref>Bone marrow aspirates show clusters of these neoplastic cells, with a mixed pattern of involvement including diffuse and interstitial, in trephine core biopsy.<ref name=":6" />
 
==Immunophenotype==
 
==Immunophenotype==
T-cell prolymphocytes show strong staining with alpha-naphthyl acetate esterase and acid phosphatase, presenting a distinctive dot-like pattern, but cytochemistry is not commonly used for diagnosis.<ref>{{Cite journal|last=Yang|first=K.|last2=Bearman|first2=R. M.|last3=Pangalis|first3=G. A.|last4=Zelman|first4=R. J.|last5=Rappaport|first5=H.|date=1982-08|title=Acid phosphatase and alpha-naphthyl acetate esterase in neoplastic and non-neoplastic lymphocytes. A statistical analysis|url=https://pubmed.ncbi.nlm.nih.gov/6179423|journal=American Journal of Clinical Pathology|volume=78|issue=2|pages=141–149|doi=10.1093/ajcp/78.2.141|issn=0002-9173|pmid=6179423}}</ref> T-cell prolymphocytes exhibit a post-thymic T-cell phenotype. In 60% of cases, the cells are CD4+ and CD8-. In 25% of cases, they co-express both CD4 and CD8, while the remaining 15% are CD4- and CD8+.<ref name=":7">Matutes E, et al., (2017). T-cell prolymphocytic leukemia, 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, p346-347.</ref>  
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'''Cytochemistry:''' T-cell prolymphocytes show strong staining with alpha-naphthyl acetate esterase and acid phosphatase, presenting a distinctive dot-like pattern, but cytochemistry is not commonly used for diagnosis.<ref>{{Cite journal|last=Yang|first=K.|last2=Bearman|first2=R. M.|last3=Pangalis|first3=G. A.|last4=Zelman|first4=R. J.|last5=Rappaport|first5=H.|date=1982-08|title=Acid phosphatase and alpha-naphthyl acetate esterase in neoplastic and non-neoplastic lymphocytes. A statistical analysis|url=https://pubmed.ncbi.nlm.nih.gov/6179423|journal=American Journal of Clinical Pathology|volume=78|issue=2|pages=141–149|doi=10.1093/ajcp/78.2.141|issn=0002-9173|pmid=6179423}}</ref>  
 +
 
 +
'''Immunophenotype:''' T-cell prolymphocytes exhibit a post-thymic T-cell phenotype. In 60% of cases, the cells are CD4+ and CD8-. In 25% of cases, they co-express both CD4 and CD8, while the remaining 15% are CD4- and CD8+.<ref name=":7">Matutes E, et al., (2017). T-cell prolymphocytic leukemia, 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, p346-347.</ref>  
 
{| class="wikitable sortable"
 
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==Chromosomal Rearrangements (Gene Fusions)==
 
==Chromosomal Rearrangements (Gene Fusions)==
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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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" />
 
{| class="wikitable sortable"
 
{| class="wikitable sortable"
 
|-
 
|-
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|Yes
 
|Yes
 
|Yes
 
|Yes
|These genetic abnormalities serve as diagnostic markers and generally indicate an aggressive disease. This is due to their role in overexpressing oncogenes like ''TCL1A''. Major diagnostic criteria.<ref name=":6" />
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|These genetic abnormalities serve as diagnostic markers and generally indicate an aggressive disease. This is due to their role in overexpressing oncogenes like ''TCL1A''. '''Major diagnostic criteria'''.<ref name=":6" />
 
|-
 
|-
 
|t(X;14)(q28;q11.2)
 
|t(X;14)(q28;q11.2)
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|No
 
|No
 
|Yes
 
|Yes
|Major diagnostic criteria.<ref name=":6" />
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|'''Major diagnostic criteria'''.<ref name=":6" />
 
|}
 
|}
 
==Individual Region Genomic Gain / Loss / LOH==
 
==Individual Region Genomic Gain / Loss / LOH==
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|No
 
|No
 
|No
 
|No
|Recurrent secondary finding (70-80% of cases). Minor diagnostic criteria.<ref name=":6">{{Cite journal|last=Staber|first=Philipp B.|last2=Herling|first2=Marco|last3=Bellido|first3=Mar|last4=Jacobsen|first4=Eric D.|last5=Davids|first5=Matthew S.|last6=Kadia|first6=Tapan Mahendra|last7=Shustov|first7=Andrei|last8=Tournilhac|first8=Olivier|last9=Bachy|first9=Emmanuel|date=2019-10-03|title=Consensus criteria for diagnosis, staging, and treatment response assessment of T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/31292114|journal=Blood|volume=134|issue=14|pages=1132–1143|doi=10.1182/blood.2019000402|issn=1528-0020|pmc=7042666|pmid=31292114}}</ref>
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|Recurrent secondary finding (70-80% of cases). '''Minor diagnostic criteria'''.<ref name=":6">{{Cite journal|last=Staber|first=Philipp B.|last2=Herling|first2=Marco|last3=Bellido|first3=Mar|last4=Jacobsen|first4=Eric D.|last5=Davids|first5=Matthew S.|last6=Kadia|first6=Tapan Mahendra|last7=Shustov|first7=Andrei|last8=Tournilhac|first8=Olivier|last9=Bachy|first9=Emmanuel|date=2019-10-03|title=Consensus criteria for diagnosis, staging, and treatment response assessment of T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/31292114|journal=Blood|volume=134|issue=14|pages=1132–1143|doi=10.1182/blood.2019000402|issn=1528-0020|pmc=7042666|pmid=31292114}}</ref>
 
|-
 
|-
 
|5
 
|5
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|Yes
 
|Yes
 
|No
 
|No
|Minor diagnostic criteria.<ref name=":6" />
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|'''Minor diagnostic criteria'''.<ref name=":6" />
 
|-
 
|-
 
|6
 
|6
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|Yes
 
|Yes
 
|Yes
 
|Yes
|Frequent, Minor diagnostic criteria.<ref name=":6" />
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|Frequent, '''Minor diagnostic criteria'''.<ref name=":6" />
 
|-
 
|-
 
|12
 
|12
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|No
 
|No
 
|Haploinsufficiency of the CDKN1B gene at the 12p13 locus contributes to the development of T-PLL.<ref>{{Cite journal|last=Le Toriellec|first=Emilie|last2=Despouy|first2=Gilles|last3=Pierron|first3=Gaëlle|last4=Gaye|first4=Nogaye|last5=Joiner|first5=Marjorie|last6=Bellanger|first6=Dorine|last7=Vincent-Salomon|first7=Anne|last8=Stern|first8=Marc-Henri|date=2008-02-15|title=Haploinsufficiency of CDKN1B contributes to leukemogenesis in T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/18073348|journal=Blood|volume=111|issue=4|pages=2321–2328|doi=10.1182/blood-2007-06-095570|issn=0006-4971|pmid=18073348}}</ref>
 
|Haploinsufficiency of the CDKN1B gene at the 12p13 locus contributes to the development of T-PLL.<ref>{{Cite journal|last=Le Toriellec|first=Emilie|last2=Despouy|first2=Gilles|last3=Pierron|first3=Gaëlle|last4=Gaye|first4=Nogaye|last5=Joiner|first5=Marjorie|last6=Bellanger|first6=Dorine|last7=Vincent-Salomon|first7=Anne|last8=Stern|first8=Marc-Henri|date=2008-02-15|title=Haploinsufficiency of CDKN1B contributes to leukemogenesis in T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/18073348|journal=Blood|volume=111|issue=4|pages=2321–2328|doi=10.1182/blood-2007-06-095570|issn=0006-4971|pmid=18073348}}</ref>
Minor diagnostic criteria.<ref name=":6" />
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'''Minor diagnostic criteria'''.<ref name=":6" />
 
|-
 
|-
 
|13
 
|13
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|No
 
|No
 
|No
 
|No
|Minor diagnostic criteria.<ref name=":6" />
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|'''Minor diagnostic criteria'''.<ref name=":6" />
 
|-
 
|-
 
|17
 
|17
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|No
 
|No
 
|Leading to the dysregulation of genes such as BCL11B, which is crucial in T-cell development and function.<ref name=":0" />
 
|Leading to the dysregulation of genes such as BCL11B, which is crucial in T-cell development and function.<ref name=":0" />
Minor diagnostic criteria.<ref name=":6" />
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'''Minor diagnostic criteria'''.<ref name=":6" />
 
|}
 
|}
==Diagnosis and Characteristic Chromosomal Patterns==
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==Diagnostic criteria==
[[File:Inv(14)(q11.2q32).png|thumb|Inv(14)(q11.2q32)]]Diagnosis requires either all three major criteria or the first two major criteria along with one minor criterion:<ref name=":5" />
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Diagnosis requires either all three major criteria or the first two major criteria along with one minor criterion:<ref name=":5" />
    
*'''Major criteria:'''
 
*'''Major criteria:'''
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**Involvement of specific sites (spleen, effusions)
 
**Involvement of specific sites (spleen, effusions)
    +
== Characteristic Chromosomal Patterns ==
 +
[[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" />
 
{| class="wikitable sortable"
 
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|Yes
 
|Yes
 
|Yes
 
|Yes
|he 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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|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)
 
|}
 
|}
 
==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. AS deletions and mutations of the ATM gene, present in up to 90% of T-PLL cases but typically absent in other mature T-cell malignancies, are considered highly indicative in diagnosing suspected TCL1 family-negative T-PLL. <ref name=":8">{{Cite journal|last=Schrader|first=A.|last2=Crispatzu|first2=G.|last3=Oberbeck|first3=S.|last4=Mayer|first4=P.|last5=Pützer|first5=S.|last6=von Jan|first6=J.|last7=Vasyutina|first7=E.|last8=Warner|first8=K.|last9=Weit|first9=N.|date=2018-02-15|title=Actionable perturbations of damage responses by TCL1/ATM and epigenetic lesions form the basis of T-PLL|url=https://pubmed.ncbi.nlm.nih.gov/29449575|journal=Nature Communications|volume=9|issue=1|pages=697|doi=10.1038/s41467-017-02688-6|issn=2041-1723|pmc=5814445|pmid=29449575}}</ref><ref name=":3" />
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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. As deletions and mutations of the ATM gene, present in up to 90% of T-PLL cases but typically absent in other mature T-cell malignancies, they are considered highly indicative in diagnosing suspected TCL1 family-negative T-PLL. <ref name=":8">{{Cite journal|last=Schrader|first=A.|last2=Crispatzu|first2=G.|last3=Oberbeck|first3=S.|last4=Mayer|first4=P.|last5=Pützer|first5=S.|last6=von Jan|first6=J.|last7=Vasyutina|first7=E.|last8=Warner|first8=K.|last9=Weit|first9=N.|date=2018-02-15|title=Actionable perturbations of damage responses by TCL1/ATM and epigenetic lesions form the basis of T-PLL|url=https://pubmed.ncbi.nlm.nih.gov/29449575|journal=Nature Communications|volume=9|issue=1|pages=697|doi=10.1038/s41467-017-02688-6|issn=2041-1723|pmc=5814445|pmid=29449575}}</ref><ref name=":3" />
 
{| class="wikitable sortable"
 
{| class="wikitable sortable"
 
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|Yes
 
|Yes
 
|Yes (PARP inhibitors, NCT03263637)
 
|Yes (PARP inhibitors, NCT03263637)
|Deletions of or missense mutations at the ''ATM'' locus are found in up to 80% to 90% of T-PLL cases.<ref name=":8" /> ATM alterations can serve as a minor diagnostic criterion.<ref name=":6" />
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|Since deletions of or missense mutations at the ''ATM'' locus are found in up to 80% to 90% of T-PLL cases, ''ATM'' alterations can serve as a minor diagnostic criterion.<ref name=":6" /><ref name=":8" />
 
|-
 
|-
 
|''FBXW10''
 
|''FBXW10''
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Research indicates that epigenetic modifications in the regulatory regions of key oncogenes and genes involved in DNA damage response and T-cell receptor regulation are clearly present. These changes are closely associated with the transcriptional dysregulation that forms the core lesions of T-PLL.<ref>{{Cite journal|last=Tian|first=Shulan|last2=Zhang|first2=Henan|last3=Zhang|first3=Pan|last4=Kalmbach|first4=Michael|last5=Lee|first5=Jeong-Heon|last6=Ordog|first6=Tamas|last7=Hampel|first7=Paul J.|last8=Call|first8=Timothy G.|last9=Witzig|first9=Thomas E.|date=2021-04-15|title=Epigenetic alteration contributes to the transcriptional reprogramming in T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/33859327|journal=Scientific Reports|volume=11|issue=1|pages=8318|doi=10.1038/s41598-021-87890-9|issn=2045-2322|pmc=8050249|pmid=33859327}}</ref>
 
Research indicates that epigenetic modifications in the regulatory regions of key oncogenes and genes involved in DNA damage response and T-cell receptor regulation are clearly present. These changes are closely associated with the transcriptional dysregulation that forms the core lesions of T-PLL.<ref>{{Cite journal|last=Tian|first=Shulan|last2=Zhang|first2=Henan|last3=Zhang|first3=Pan|last4=Kalmbach|first4=Michael|last5=Lee|first5=Jeong-Heon|last6=Ordog|first6=Tamas|last7=Hampel|first7=Paul J.|last8=Call|first8=Timothy G.|last9=Witzig|first9=Thomas E.|date=2021-04-15|title=Epigenetic alteration contributes to the transcriptional reprogramming in T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/33859327|journal=Scientific Reports|volume=11|issue=1|pages=8318|doi=10.1038/s41598-021-87890-9|issn=2045-2322|pmc=8050249|pmid=33859327}}</ref>
 
==Genes and Main Pathways Involved==
 
==Genes and Main Pathways Involved==
The genetic landscape of T-PLL highlights the deregulation of DNA repair mechanisms and epigenetic modulators, alongside the frequent mutational activation of the IL2RG-JAK1-JAK3-STAT5B pathway in the pathogenesis of T-PLL.<ref name=":6" />
+
The key pathways involved in the pathogenesis of T-cell prolymphocytic leukemia (T-PLL) include DNA damage repair, T-cell receptor (''TCR'') signaling, and epigenetic modulation. Additionally, there is frequent mutational activation of the ''IL2RG-JAK1-JAK3-STAT5B'' pathway, which plays a significant role in the disease's development and progression.<ref name=":6" />
 
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==Genetic Diagnostic Testing Methods==
 
==Genetic Diagnostic Testing Methods==
Cytogenetics (FISH, CpG-stimulated Karyotype, SNP microarray), PCR for TRB/TRG and Next-Generation Sequencing (NGS). The genetic diagnostic process involves detecting clonal rearrangements of the TR gene and rearrangements of the TCL1 gene at the TRB or TRG loci.
+
Cytogenetics (FISH, CpG-stimulated Karyotype, SNP microarray), PCR for TRB/TRG and Next-Generation Sequencing (NGS). The genetic diagnostic process involves detecting clonal rearrangements of the TR gene and rearrangements of the ''TCL1'' gene at the ''TRB'' or ''TRG'' loci.
 
==Familial Forms==
 
==Familial Forms==
There is no noticeable familial clustering. However, a subset of cases may develop in the context of ataxia-telangiectasia (AT), which is characterized by germline mutations in the ATM gene. Here there is a combined heterozygosity in the form of biallelic inactivating mutations of the ''ATM'' tumor suppressor gene.<ref>{{Cite journal|last=Suarez|first=Felipe|last2=Mahlaoui|first2=Nizar|last3=Canioni|first3=Danielle|last4=Andriamanga|first4=Chantal|last5=Dubois d'Enghien|first5=Catherine|last6=Brousse|first6=Nicole|last7=Jais|first7=Jean-Philippe|last8=Fischer|first8=Alain|last9=Hermine|first9=Olivier|date=2015-01-10|title=Incidence, presentation, and prognosis of malignancies in ataxia-telangiectasia: a report from the French national registry of primary immune deficiencies|url=https://pubmed.ncbi.nlm.nih.gov/25488969|journal=Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology|volume=33|issue=2|pages=202–208|doi=10.1200/JCO.2014.56.5101|issn=1527-7755|pmid=25488969}}</ref> Penetrance of the tumor phenotype is about 10% to 15% by early adulthood.<ref>{{Cite journal|last=Taylor|first=A. M.|last2=Metcalfe|first2=J. A.|last3=Thick|first3=J.|last4=Mak|first4=Y. F.|date=1996-01-15|title=Leukemia and lymphoma in ataxia telangiectasia|url=https://pubmed.ncbi.nlm.nih.gov/8555463|journal=Blood|volume=87|issue=2|pages=423–438|issn=0006-4971|pmid=8555463}}</ref> It represents nearly 3% of all malignancies in patients with ataxia-telangiectasia.<ref>{{Cite journal|last=Li|first=Geling|last2=Waite|first2=Emily|last3=Wolfson|first3=Julie|date=2017-12-26|title=T-cell prolymphocytic leukemia in an adolescent with ataxia-telangiectasia: novel approach with a JAK3 inhibitor (tofacitinib)|url=https://pubmed.ncbi.nlm.nih.gov/29296924|journal=Blood Advances|volume=1|issue=27|pages=2724–2728|doi=10.1182/bloodadvances.2017010470|issn=2473-9529|pmc=5745136|pmid=29296924}}</ref>
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While there is no noticeable familial clustering of T-cell prolymphocytic leukemia (T-PLL), a subset of cases can develop in the context of ataxia-telangiectasia (AT). AT is characterized by germline mutations in the ATM gene, and patients with AT are at an increased risk for various malignancies, including T-PLL. In these cases, biallelic inactivation of the ATM tumor suppressor gene occurs, with about 10% to 15% penetrance of the tumor phenotype by early adulthood. T-PLL represents nearly 3% of all malignancies in patients with ataxia-telangiectasia​. <ref>{{Cite journal|last=Suarez|first=Felipe|last2=Mahlaoui|first2=Nizar|last3=Canioni|first3=Danielle|last4=Andriamanga|first4=Chantal|last5=Dubois d'Enghien|first5=Catherine|last6=Brousse|first6=Nicole|last7=Jais|first7=Jean-Philippe|last8=Fischer|first8=Alain|last9=Hermine|first9=Olivier|date=2015-01-10|title=Incidence, presentation, and prognosis of malignancies in ataxia-telangiectasia: a report from the French national registry of primary immune deficiencies|url=https://pubmed.ncbi.nlm.nih.gov/25488969|journal=Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology|volume=33|issue=2|pages=202–208|doi=10.1200/JCO.2014.56.5101|issn=1527-7755|pmid=25488969}}</ref> <ref>{{Cite journal|last=Taylor|first=A. M.|last2=Metcalfe|first2=J. A.|last3=Thick|first3=J.|last4=Mak|first4=Y. F.|date=1996-01-15|title=Leukemia and lymphoma in ataxia telangiectasia|url=https://pubmed.ncbi.nlm.nih.gov/8555463|journal=Blood|volume=87|issue=2|pages=423–438|issn=0006-4971|pmid=8555463}}</ref> <ref>{{Cite journal|last=Li|first=Geling|last2=Waite|first2=Emily|last3=Wolfson|first3=Julie|date=2017-12-26|title=T-cell prolymphocytic leukemia in an adolescent with ataxia-telangiectasia: novel approach with a JAK3 inhibitor (tofacitinib)|url=https://pubmed.ncbi.nlm.nih.gov/29296924|journal=Blood Advances|volume=1|issue=27|pages=2724–2728|doi=10.1182/bloodadvances.2017010470|issn=2473-9529|pmc=5745136|pmid=29296924}}</ref>
 
==Additional Information==
 
==Additional Information==
In T-PLL, the rapid growth of the disease necessitates immediate initiation of treatment. The most effective first-line treatment is alemtuzumab, an anti-CD52 antibody with remission rates over 80%. However, these remissions usually last only 1-2 years. To potentially extend remission, eligible patients are advised to undergo allogeneic blood stem cell transplantation (allo-SCT) during their first complete remission, which can lead to longer remission durations of over 4-5 years for 15-30% of patients. Consequently, the prognosis for T-PLL remains poor, with median overall survival times under two years and five-year survival rates below 5%[https://clinicaltrials.gov/study/NCT03989466 . Ongoing research is exploring molecularly targeted drugs and signaling pathway inhibitors, for routine clinical use in treating T-PLL.]
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In T-PLL, the rapid growth of the disease necessitates immediate initiation of treatment. The most effective first-line treatment is alemtuzumab, an anti-CD52 antibody with remission rates over 80%. However, these remissions usually last only 1-2 years. To potentially extend remission, eligible patients are advised to undergo allogeneic blood stem cell transplantation (allo-SCT) during their first complete remission, which can lead to longer remission durations of over 4-5 years for 15-30% of patients. Consequently, the prognosis for T-PLL remains poor, with median overall survival times under two years and five-year survival rates below 5%[https://clinicaltrials.gov/study/NCT03989466 . Ongoing studies are exploring molecularly targeted drugs and signaling pathway inhibitors, for routine clinical use in treating T-PLL.]
 
==Links==
 
==Links==
 
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