<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|This page was converted to the new template on 2023-11-30. The original page can be found at [[HAEM4:Anaplastic Large Cell Lymphoma, ALK-Positive]].
<blockquote class='blockedit'>{{Box-round|title=HAEM5 Conversion Notes|This page was converted to the new template on 2023-12-04. The original page can be found at [[HAEM4:Anaplastic Large Cell Lymphoma, ALK-Positive]].
Anaplastic Large Cell Lymphoma, ALK-Positive (ALK+ ALCL) is a T-cell lymphoma characterized by usually large lymphoma cells with abundant cytoplasm and pleomorphic nuclei, often horse-shoe shaped (see Morphologic Features below), with a chromosomal rearrangement involving the ALK gene resulting in expression of ALK protein and CD30
Synonyms / Terminology
Ki-1 (CD30) lymphoma - obsolete
Epidemiology / Prevalence
ALCL (ALK+, ALK-, and primary cutaneous) account for <5% of all cases of non-Hodgkin lymphoma (NHL)[1]
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Most patients (70%) present with advanced (stage III-IV) disease and B-symptoms.[2]
Sites of Involvement
Lymph nodes and extranodal sites (most commonly skin, bone, soft tissue, lungs and liver)
Bone marrow involvement detected in 30% when using immunohistochemistry (CD30 and EMA). Can miss marrow involvement by H&E evaluation alone, which detects involvement with ~10% incidence.[3]
Lymphoma cells characterized by eccentric, horseshoe-shaped or kidney-shaped nuclei, often with eosinophilic cytoplasm accentuated near the nucleus
Usually large in size, but may also be smaller
Present in varying proportions
Seen in all morphological variants/patterns of ALK+ ALCL
Morphological variants/patterns
Common (60%): predominant population of large hallmark cells
Lymphohistiocytic (10%): lymphoma cells are admixed with numerous reactive histiocytes that may obscure the lymphoma cells; lymphoma cells often cluster around vessels and are often smaller than in the common pattern
Small cell (5-10%): predominant population of smaller lymphoma cells; hallmark cells are often concentrated around vessels; may also see "fried egg cells" (pale cytoplasm with central nucleus) or signet ring-like cells; can misdiagnose of peripheral T-cell lymphoma, NOS
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ALK+ ALCL show the following staining pattern[6][7]:
CD30+: Cell membrane and Golgi; large lymphoma cells show strongest staining; smaller cells may show weak, partial to negative staining
ALK+: cellular location of ALK staining varies depending on ALK translocation partner. In the most common t(2;5), most cases show both cytoplasmic and nuclear ALK staining. In the small cell variant, staining is usually restricted to the nucleus
EMA+: some cases show positivity in only a proportion of lymphoma cells
CD3(-): >75% of cases are CD3-negative
CD4>>>CD8
CD2 and CD5: Majority positive
Cytotoxic marker(s)+: TIA1, granzyme B and/or perforin
CD45: variably positive
CD25+
BCL2-negative
Chromosomal Rearrangements (Gene Fusions)
Put your text here and fill in the table
Chromosomal Rearrangement
Genes in Fusion (5’ or 3’ Segments)
Pathogenic Derivative
Prevalence
Diagnostic Significance (Yes, No or Unknown)
Prognostic Significance (Yes, No or Unknown)
Therapeutic Significance (Yes, No or Unknown)
Notes
EXAMPLE t(9;22)(q34;q11.2)
EXAMPLE 3'ABL1 / 5'BCR
EXAMPLE der(22)
EXAMPLE 20% (COSMIC)
EXAMPLE 30% (add reference)
Yes
No
Yes
EXAMPLE
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).
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ALK(+) ALCL is characterized by chromosomal translocations involving ALK gene, a receptor tyrosine kinase domain at 2p23.
Approximately 80% of cases show a cytogenetic translocation t(2;5) (NPM1-ALK, t(2;5)(p23;q35)) which fuses the ALK gene to the nucleophosmine (NPM) gene at 5q35, resulting in the overexpression and constitutive activation of a chimeric ALK fusion protein, which plays an important role in ALK-mediated oncogenesis.[8]
FISH break apart probe for ALK gene showing a split signal indicating ALK rearrangement in a case of ALK(+) ALCL.
Table below shows described ALK translocations with ALK staining pattern, and frequency of cases. Of note, identifying the ALK fusion partner is not considered necessary in routine clinical practice.
editv4:Clinical Significance (Diagnosis, Prognosis and Therapeutic Implications).
Please incorporate this section into the relevant tables found in:
Chromosomal Rearrangements (Gene Fusions)
Individual Region Genomic Gain/Loss/LOH
Characteristic Chromosomal Patterns
Gene Mutations (SNV/INDEL)
Diagnosis
As stated above, the diagnosis is based on histology and immunohistochemistry
FISH is not required for diagnosis in routine practice [32][33]
Prognosis
ALK+ ALCL has a better survival rate compared to ALK-negative ALCL
However, differences in patient age (younger in ALK+) may account for this better survival[34]
Different ALK translocation partners do not have prognostic significance
Survival is predicted by International Prognostic Index (IPI) with overall long term survival rate approaching 80%
Detecting minimal residual disease by PCR for NPM1-ALK (not readily commercially available) in bone marrow and peripheral blood during treatment could identify patients at risk of relapse[35]
Small-cell or lymphohistiocytic patterns tend to present with disseminated disease and have a less favorable prognosis than the common pattern[36]
ALK inhibition (crizotinib) can be an effective 2nd-line therapeutic strategy as ALK is essential for the proliferation and survival of ALK+ ALCL cells[39][38][40]
Drug resistance may develop due to:
Mutations of the ALK gene impairing binding of the inhibitor[41]; other ALK inhibitors are not currently FDA-approved for use in ALK+ ALCL
See also gene mutations section above
Engagement of other cell signaling pathways
Preclinical models suggest role of:
Combination therapy with hypomethylating agents (such as azacitidine) and epigenetic modifying drugs (such as romidepsin, a histone deacetylase inhibitor)[42]
NOTCH1 inhibition by γ-secretase inhibitors (GSI) in combination with crizotinib may provide synergistic anti-tumor activity, or as a single agent in ALK-inhibitor resistant cell lines[37]
Individual Region Genomic Gain / Loss / LOH
Put your text here and fill in the table (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.)
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
EXAMPLE
7
EXAMPLE Loss
EXAMPLE
chr7:1- 159,335,973 [hg38]
EXAMPLE
chr7
Yes
Yes
No
EXAMPLE
Presence of monosomy 7 (or 7q deletion) is sufficient for a diagnosis of AML with MDS-related changes when there is ≥20% blasts and no prior therapy (add reference). Monosomy 7/7q deletion is associated with a poor prognosis in AML (add reference).
EXAMPLE
8
EXAMPLE Gain
EXAMPLE
chr8:1-145,138,636 [hg38]
EXAMPLE
chr8
No
No
No
EXAMPLE
Common recurrent secondary finding for t(8;21) (add reference).
Put your text here (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)
Chromosomal Pattern
Diagnostic Significance (Yes, No or Unknown)
Prognostic Significance (Yes, No or Unknown)
Therapeutic Significance (Yes, No or Unknown)
Notes
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).
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See other sections.
Gene Mutations (SNV / INDEL)
Put your text here and fill in the table (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.)
JAK1, STAT3: Mutations described in ALK(-) ALCL[46], and breast implant-associated anaplastic large cell lymphoma (BIA-ALCL)[47]
RHOA, DNMT3A, CD28: Mutations described in peripheral T cell-lymphoma (PTCL), NOS, and in angioimmunoblastic T-cell lymphoma (AITL)[48]
IDH2 mutations are relatively specific for AITL[49][50]
A variety of mechanisms for the acquired resistance to ALK inhibitors, such as crizotinib, have been described:
ALK kinase domain secondary mutations, including L1196 M, G1269A, L1152R, C1156Y, I1171T, F1174 L, G1202R, and S1206Y, have been identified as the key mechanism of resistance[51][52][53][54][55][56][57]
The G1269A mutation, in which the glycine at 1269 is substituted with an alanine, causes steric hindrance, resulting in decreased affinity for crizotinib.[58][59]
Gain in ALK copy number and loss of ALK gene rearrangement have also been implicated in the development of acquired resistance to crizotinib.[53][54][55]
Epigenomic Alterations
NPM-ALK via STAT3-activated DNA methyltransferases[60] uses epigenetic silencing mechanisms to:
Downregulate tumor suppressor genes to maintain its own expression (i.e. to inhibit downregulation of NPM-ALK). Silenced tumor suppressors include:
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Activation of the ALK catalytic domain leads to the oncogenic properties of the ALK protein, leading to activation of multiple signaling cascades including[68]:
RAS-ERK
JAK/STAT
STAT3 is a pivotal transcription factor in most ALCL subtypes:
NPM1/ALK and variants lead to expression of ALK fusion proteins with constitutive ALK tyrosine kinase activity, which converges in the activation of the downstream oncogenic transcription factor STAT3[46][48].
In the absence of ALK fusions there are activation JAK1 and/or STAT3 mutations in ALK(-) ALCL [46], and some BIA-ALCL. [69].
PI3K/AKT/mTOR
ALK-NPM-STAT3 induces:
See Epigenomics section above
TGF beta, IL-10, PD-L1/CD274 to create immunosuppressive microenvironment and evasion of immune system[70][71][72]
HIF1α expression induces expression of VEGF (tumor angiogenesis); allows lymphoma cells to adapt to hypoxic conditions[73]
Expression of embryonic genes (SOX2, SALL4) promoting stem cell-like program
Deregulation of microRNAs (miR-155, miR-101, miR-17-92 cluster, miR-26a, miR-16)[74][75][76][77][78]
Genetic Diagnostic Testing Methods
Diagnosis is based on histologic evaluation and immunohistochemical positivity for CD30 and ALK on the T-lymphoma cells.
FISH using an ALK breakapart probe or karyotype analysis can detect ALK translocations, but is not required for diagnosis as it can be established by morphology and immunohistochemistry.
Familial Forms
None
Additional Information
None
Links
See References.
References
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↑ 1.01.11.2Arber DA, et al., (2017). Anaplastic large cell lymphoma, ALK-positive, 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, p413-418.
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*Citation of this Page: “ALK-positive anaplastic large cell lymphoma”. Compendium of Cancer Genome Aberrations (CCGA), Cancer Genomics Consortium (CGC), updated 12/4/2023, https://ccga.io/index.php/HAEM5:ALK-positive_anaplastic_large_cell_lymphoma.