HAEM5:T-prolymphocytic leukaemia: Difference between revisions

Parastou Tizro, MD, Celeste C. Eno, PhD, Sumire Kitahara, MD

Cedars-Sinai, Los Angeles, CA

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Put your text here and fill in the table <span style="color:#0070C0">(''Instructions: Details on clinical significance such as prognosis and other important information can be provided in the notes section. Please include references throughout the table. Do not delete the table.'')</span>

!Driver Gene!!Fusion(s) and Common Partner Genes!!Molecular Pathogenesis!!Typical Chromosomal Alteration(s)

|<span class="blue-text">EXAMPLE:</span> ''ABL1''||<span class="blue-text">EXAMPLE:</span> ''BCR::ABL1''||<span class="blue-text">EXAMPLE:</span> The pathogenic derivative is the der(22) resulting in fusion of 5’ BCR and 3’ABL1.||<span class="blue-text">EXAMPLE:</span> t(9;22)(q34;q11.2)

|<span class="blue-text">EXAMPLE:</span> Common (CML)

|<span class="blue-text">EXAMPLE:</span> D, P, T

The t(9;22) is diagnostic of CML in the appropriate morphology and clinical context (add reference). This fusion is responsive to targeted therapy such as Imatinib (Gleevec) (add reference). BCR::ABL1 is generally favorable in CML (add reference).

|-

|<span class="blue-text">EXAMPLE:</span> ''CIC''

|<span class="blue-text">EXAMPLE:</span> Typically, the last exon of ''CIC'' is fused to ''DUX4''. The fusion breakpoint in ''CIC'' is usually intra-exonic and removes an inhibitory sequence, upregulating ''PEA3'' genes downstream of ''CIC'' including ''ETV1'', ''ETV4'', and ''ETV5''.

 

|<span class="blue-text">EXAMPLE:</span> ''ALK''

 

 

|<span class="blue-text">EXAMPLE:</span> Fusions result in constitutive activation of the ''ALK'' tyrosine kinase. The most common ''ALK'' fusion is ''EML4::ALK'', with breakpoints in intron 19 of ''ALK''. At the transcript level, a variable (5’) partner gene is fused to 3’ ''ALK'' at exon 20. Rarely, ''ALK'' fusions contain exon 19 due to breakpoints in intron 18.

|<span class="blue-text">EXAMPLE:</span> N/A

|<span class="blue-text">EXAMPLE:</span> Rare (Lung adenocarcinoma)

 

Both balanced and unbalanced forms are observed by FISH (add references).

|<span class="blue-text">EXAMPLE:</span> Intragenic deletion of exons 2–7 in ''EGFR'' removes the ligand-binding domain, resulting in a constitutively active tyrosine kinase with downstream activation of multiple oncogenic pathways.

|<span class="blue-text">EXAMPLE:</span> N/A

|<span class="blue-text">EXAMPLE:</span> D, P, T

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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">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>

!Chromosomal Rearrangement!!Genes in Fusion (5’ or 3’ Segments)!!Pathogenic Derivative!!Prevalence

!Prognostic Significance (Yes, No or Unknown)

|-

t(14;14)(q11.2;q32.1)

|''TCL1A/B ,TRD''|| ||inv(14) ~60%

t(14;14) ~25%

|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" />

|''MTCP1, TRD''

|Low (5%)

|Yes

|No

|'''Major diagnostic criteria'''.<ref name=":6" />

 

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">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>  

!Chr #!!Gain / Loss / Amp / LOH!!Minimal Region Genomic Coordinates [Genome Build]!!Minimal Region Cytoband

!Diagnostic Significance (Yes, No or Unknown)

!Prognostic Significance (Yes, No or Unknown)

!Therapeutic Significance (Yes, No or Unknown)

!Notes

trisomy 8q<br />8q24 (''MYC'')

|Yes

|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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|Yes

|'''Minor diagnostic criteria'''.<ref name=":6" />

|gain of 6p, loss of 6q <ref>{{Cite journal|last=Dearden|first=Claire|date=2012-07-19|title=How I treat prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/22649104|journal=Blood|volume=120|issue=3|pages=538–551|doi=10.1182/blood-2012-01-380139|issn=1528-0020|pmid=22649104}}</ref><ref>{{Cite journal|last=Soulier|first=J.|last2=Pierron|first2=G.|last3=Vecchione|first3=D.|last4=Garand|first4=R.|last5=Brizard|first5=F.|last6=Sigaux|first6=F.|last7=Stern|first7=M. H.|last8=Aurias|first8=A.|date=2001-07|title=A complex pattern of recurrent chromosomal losses and gains in T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/11391795|journal=Genes, Chromosomes & Cancer|volume=31|issue=3|pages=248–254|doi=10.1002/gcc.1141|issn=1045-2257|pmid=11391795}}</ref>

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|No

|11q

|ch11q21-q23.3

|Yes

|Yes

|Yes (poor)

|Frequent, '''Minor diagnostic criteria'''.<ref name=":6" />

|Yes

|Yes

|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" />

|Yes

|No

|'''Minor diagnostic criteria'''.<ref name=":6" />

|Yes

|Yes (resistance to therapy)

del(22q)

22q11-12 <ref>{{Cite journal|last=Stengel|first=Anna|last2=Kern|first2=Wolfgang|last3=Zenger|first3=Melanie|last4=Perglerová|first4=Karolina|last5=Schnittger|first5=Susanne|last6=Haferlach|first6=Torsten|last7=Haferlach|first7=Claudia|date=2014-12-06|title=A Comprehensive Cytogenetic and Molecular Genetic Characterization of Patients with T-PLL Revealed Two Distinct Genetic Subgroups and JAK3 Mutations As an Important Prognostic Marker|url=https://doi.org/10.1182/blood.V124.21.1639.1639|journal=Blood|volume=124|issue=21|pages=1639–1639|doi=10.1182/blood.v124.21.1639.1639|issn=0006-4971}}</ref><ref name=":0">{{Cite journal|last=Fang|first=Hong|last2=Beird|first2=Hannah C.|last3=Wang|first3=Sa A.|last4=Ibrahim|first4=Andrew F.|last5=Tang|first5=Zhenya|last6=Tang|first6=Guilin|last7=You|first7=M. James|last8=Hu|first8=Shimin|last9=Xu|first9=Jie|date=2023-09|title=T-prolymphocytic leukemia: TCL1 or MTCP1 rearrangement is not mandatory to establish diagnosis|url=https://pubmed.ncbi.nlm.nih.gov/37443196|journal=Leukemia|volume=37|issue=9|pages=1919–1921|doi=10.1038/s41375-023-01956-3|issn=1476-5551|pmid=37443196}}</ref>

 

(most common)

|Yes

|No

'''Minor diagnostic criteria'''.<ref name=":6" />

Put your text here and fill in the table <span style="color:#0070C0">(I''nstructions: Included in this category are alterations such as 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; microsatellite instability; homologous recombination deficiency; mutational signature pattern; etc. Details on clinical significance such as prognosis and other important information can be provided in the notes section. Please include references throughout the table. Do not delete the table.'')</span>

!'''Prevalence -'''

'''Common >20%, Recurrent 5-20% or Rare <5% (Disease)'''

!'''Diagnostic, Prognostic, and Therapeutic Significance - D, P, T'''

!'''Established Clinical Significance Per Guidelines - Yes or No (Source)'''

!'''Clinical Relevance Details/Other Notes'''

 

!Notes

|Yes

|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)

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 or common as well either disease defining and/or clinically significant. If a gene has multiple mechanisms depending on the type or site of the alteration, add multiple entries 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. Details on clinical significance such as prognosis and other important information such as concomitant and mutually exclusive mutations can be provided in the notes section. Please include references throughout the table. Do not delete the table.'') </span>

!Gene!!'''Genetic Alteration'''!!'''Tumor Suppressor Gene, Oncogene, Other'''!!'''Prevalence -'''

'''Common >20%, Recurrent 5-20% or Rare <5% (Disease)'''

!'''Diagnostic, Prognostic, and Therapeutic Significance - D, P, T  '''

!'''Established Clinical Significance Per Guidelines - Yes or No (Source)'''

!'''Clinical Relevance Details/Other Notes'''

|<span class="blue-text">EXAMPLE:</span>''EGFR''

|<span class="blue-text">EXAMPLE:</span> Exon 18-21 activating mutations

|<span class="blue-text">EXAMPLE:</span> Oncogene

|<span class="blue-text">EXAMPLE:</span> Common (lung cancer)

|<span class="blue-text">EXAMPLE:</span> Yes (NCCN)

|<span class="blue-text">EXAMPLE:</span> Exons 18, 19, and 21 mutations are targetable for therapy. Exon 20 T790M variants cause resistance to first generation TKI therapy and are targetable by second and third generation TKIs (add references).

|-

|<span class="blue-text">EXAMPLE:</span> ''TP53''; Variable LOF mutations

<br />

|<span class="blue-text">EXAMPLE:</span> Variable LOF mutations

|<span class="blue-text">EXAMPLE:</span> Tumor Supressor Gene

|<span class="blue-text">EXAMPLE:</span> Common (breast cancer)

|<span class="blue-text">EXAMPLE:</span> P

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|<span class="blue-text">EXAMPLE:</span> >90% are somatic; rare germline alterations associated with Li-Fraumeni syndrome (add reference). Denotes a poor prognosis in breast cancer.

|-

|<span class="blue-text">EXAMPLE:</span> ''BRAF''; Activating mutations

|<span class="blue-text">EXAMPLE:</span> Activating mutations

|<span class="blue-text">EXAMPLE:</span> Oncogene

|<span class="blue-text">EXAMPLE:</span> Common (melanoma)

|<span class="blue-text">EXAMPLE:</span> T

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|}Note: A more extensive list of mutations can be found in [https://www.cbioportal.org/ <u>cBioportal</u>], [https://cancer.sanger.ac.uk/cosmic <u>COSMIC</u>], and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

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 for a diagnosis of 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" />

|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" />

|''JAK/STAT'' pathway

|None specified

|Unknown

|Unknown

|8% ''JAK1''

 

 

 

 

 

|''ATM, TP53'', Epigenetic modifiers <ref name=":1">{{Cite journal|last=Andersson|first=E. I.|last2=Pützer|first2=S.|last3=Yadav|first3=B.|last4=Dufva|first4=O.|last5=Khan|first5=S.|last6=He|first6=L.|last7=Sellner|first7=L.|last8=Schrader|first8=A.|last9=Crispatzu|first9=G.|date=2018-03|title=Discovery of novel drug sensitivities in T-PLL by high-throughput ex vivo drug testing and mutation profiling|url=https://pubmed.ncbi.nlm.nih.gov/28804127|journal=Leukemia|volume=32|issue=3|pages=774–787|doi=10.1038/leu.2017.252|issn=1476-5551|pmid=28804127}}</ref><ref name=":2">{{Cite journal|last=Pinter-Brown|first=Lauren C.|date=2021-12-30|title=JAK/STAT: a pathway through the maze of PTCL?|url=https://doi.org/10.1182/blood.2021014238|journal=Blood|volume=138|issue=26|pages=2747–2748|doi=10.1182/blood.2021014238|issn=0006-4971}}</ref>

|Typically, mutations within this pathway occur in a mutually exclusive manner.<ref name=":3">{{Cite journal|last=Kiel|first=Mark J.|last2=Velusamy|first2=Thirunavukkarasu|last3=Rolland|first3=Delphine|last4=Sahasrabuddhe|first4=Anagh A.|last5=Chung|first5=Fuzon|last6=Bailey|first6=Nathanael G.|last7=Schrader|first7=Alexandra|last8=Li|first8=Bo|last9=Li|first9=Jun Z.|date=2014-08-28|title=Integrated genomic sequencing reveals mutational landscape of T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/24825865|journal=Blood|volume=124|issue=9|pages=1460–1472|doi=10.1182/blood-2014-03-559542|issn=1528-0020|pmc=4148768|pmid=24825865}}</ref>

|Targeting this pathway with specific ''JAK/STAT'' pathway inhibitors, such as tofacitinib, has shown promise in preclinical studies and early clinical trials. Combining JAK/STAT inhibitors with other treatments, like BCL-2 inhibitors, may enhance therapeutic efficacy and improve outcomes for T-PLL patients<ref>{{Cite journal|last=Gomez-Arteaga|first=Alexandra|last2=Margolskee|first2=Elizabeth|last3=Wei|first3=Mike T.|last4=van Besien|first4=Koen|last5=Inghirami|first5=Giorgio|last6=Horwitz|first6=Steven|date=2019-07|title=Combined use of tofacitinib (pan-JAK inhibitor) and ruxolitinib (a JAK1/2 inhibitor) for refractory T-cell prolymphocytic leukemia (T-PLL) with a JAK3 mutation|url=https://pubmed.ncbi.nlm.nih.gov/30997845|journal=Leukemia & Lymphoma|volume=60|issue=7|pages=1626–1631|doi=10.1080/10428194.2019.1594220|issn=1029-2403|pmc=8162842|pmid=30997845}}</ref><ref>{{Cite journal|url=https://ashpublications.org/blood/article/126/23/5486/134544/Refractory-TCell-Prolymphocytic-Leukemia-with-JAK3|doi=10.1182/blood.v126.23.5486.5486}}</ref>

|Both oncogene and TSG

|''JAK/STAT'' pathway<ref name=":1" /><ref name=":2" />

|None specified

|''EZH2'' inhibitors like tazemetostat have shown efficacy in other hematologic malignancies, providing a rationale for their potential use in T-PLL

|TSG

|8% (COSMIC)

|''JAK/STAT'' pathway<ref name=":1" /><ref name=":2" />

|None specified

|TSG

|~7-20%<ref name=":8" /><ref name=":4">{{Cite journal|last=Johansson|first=Patricia|last2=Klein-Hitpass|first2=Ludger|last3=Choidas|first3=Axel|last4=Habenberger|first4=Peter|last5=Mahboubi|first5=Bijan|last6=Kim|first6=Baek|last7=Bergmann|first7=Anke|last8=Scholtysik|first8=René|last9=Brauser|first9=Martina|date=2018-01-19|title=SAMHD1 is recurrently mutated in T-cell prolymphocytic leukemia|url=https://pubmed.ncbi.nlm.nih.gov/29352181|journal=Blood Cancer Journal|volume=8|issue=1|pages=11|doi=10.1038/s41408-017-0036-5|issn=2044-5385|pmc=5802577|pmid=29352181}}</ref>

|None specified

|Yes

|Yes

|''SAMHD1'' mutations may indicate a defective DNA damage response and aggressive disease <ref name=":4" />

|TSG

|5% (COSMIC)

|''ATM, TP53, JAK/STA''T pathway, Epigenetic modifiers

|None specified

|TSG

|2% (COSMIC)

|''ATM, JAK/STA''T pathway, Epigenetic modifiers

|None specified-In a study of T-PLL case, TP53 mutations were predominantly found in patients lacking TCRA/D rearrangements.<ref name=":9" />

|}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.

* 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.]

* 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" />

* T-PLL is an uncommon disease, accounting for approximately 2% of all mature lymphoid leukemias in adults. It mainly affects older individuals, with a median onset age of 65 years, ranging from 30 to 94 years. The disorder exhibits a slight male predominance, with a male to female ratio of 1.33:1.<ref name=":5" />

* The most prevalent symptom of the disease is a leukemic presentation, characterized by a rapid, exponential increase in lymphocyte counts, which exceed 100 × 10^9/L in 75% of patients. Approximately 30% of patients may initially experience an asymptomatic, slow-progressing phase, but this typically develops into an active disease state.<ref name=":5" /><ref name=":6" />

* 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" />

* 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" />

* '''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" />

(use the "Link" icon that looks like two overlapping circles at the top of the page) <span style="color:#0070C0">(''Instructions: Highlight text to which you want to add a link in this section or elsewhere, select the "Link" icon at the top of the page, and search the name of the internal page to which you want to link this text, or enter an external internet address by including the "<nowiki>http://www</nowiki>." portion.'')</span>

<nowiki>*</nowiki>Primary authors will typically be those that initially create and complete the content of a page. If a subsequent user modifies the content and feels the effort put forth is of high enough significance to warrant listing in the authorship section, please contact the CCGA coordinators (contact information provided on the homepage).  Additional global feedback or concerns are also welcome.