Malignant Lymphomas: A multidisciplinary approach to Diagnosis and Treatment

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Malignant LymphomasA multidisciplinary approach
to Diagnosis and Treatment

• Mona F. Melhem, M.D.
• Professor, Anatomic and Clinical Pathology
• University of Pittsburgh School of Medicine
• Chief Hematopathology
• VA Medical Center of Pittsburgh

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Lymphoproliferative disorders

• Clonal proliferation of lymphocytes at different
  stages of differentiation
• They include T-cell, B-cell and Natural killer
  cell neoplasms.
• Recapitulates stages of normal lymphocyte
  differentiation
• 4 of new cancers each year
• Incidence 15/100,000

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WHO Histologic Classification of lymphocytic
Neoplasms

• Precursor B lymphoblastic leukemia/lymphoma
• CLL/Small lymphocytic lymphoma
• Lymphoplasmacytic lymphoma
• Marginal Zone Lymphoma (splenic and MALT)
• Follicular Lymphoma
• Mantle cell Lymphoma
• Primary effusion lymphoma
• Burkitts Lymphoma

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Etiology

• Epstein Barr virus in Burkitts lymphoma
• Human Herpesvirus-8/ Kaposi sarcoma virus in
  primary effusion lymphoma
• Hepatitis C virus in lymphoplasmacytic lymphoma
• Helicobacter Pylori in gastric MALT lymphomas

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Cell Markers

• As normal lymphocytes mature, they gain and/or
  loose certain surface, cytoplasmic or nuclear
  markers that distinguish every stage of
  development.
• These markers are important and are used in the
  diagnosis, and later specific treatment of
  specific neoplasms.

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Immunohistochemistry

• The poor man immunophenotyping
• Can use
• paraffin-embedded (archival)
• frozen tissues
• 5 micron section slides
• Monoclonal vs. polyclonal antibodies

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CD 20
CD 3
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CD30/Ki-1
CD15
EMA
ALK-1
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Anaplastic Large Cell Lymphoma

• AKA Ki-1 lymphoma
• CD20-, CD3 Tcells
• Ki-1 (CD30) , CD 15, ALK-1 positive
• Specific cytogenetics t(25) leading to
  anaplastic large cell kinase (ALK) ptn
  accumulation in cells
• Differential Diagnosis
• Immunoblastic Lymphoma
• B-cell Large cell lymphoma

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CD 20
CD 3
CD 10
BCL-2
Follicular lymphoma
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Follicular Lymphomas

• CD 20, CD3-, CD10, BCL-2
• Cells resemble the centrocytes or small cleaved
  cells seen normally within germinal centers
• Specific cytogenetic t(1418)

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Flowcytometry and cell sorting
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CD 3 (T cells)
CD 20 (B cells)
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Cytogenetic Chromosomal Translocations
Mantle cell lymphoma
Burkitts
Anaplastic LCL
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Laser Capture Microscope Technique (LCM)
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Principles of Laser Capture Microdissection (LCM)
Image taken from the Arcturus website at
www.arctur.com
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Standard treatment modalities

• Chemotherapy
• Radiation therapy
• Bone Marrow transplant
• Newer Chemotherapeutic agents
• - Topoisomerase I inhibitors
• - Protein kinase inhibitors

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Drug Immunoconjugates

• Deliver conventional chemotherapy to tumor sites
• High tumor-toxic doses with acceptable host
  toxicity IgG BR96-DOXORUBICIN
• Calicheamicin-Anti-CD33
• Genistein-anti-CD19

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Considerations in the design of MABS

• Specificity for tumor antigen LOW
  CROSS-REACTIVITY
• High purity and large quantities
• Design flexibility
• Customized effector functions
• Shuttle for toxic payloads

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Ideal features of tumor antigens for MAB therapy

• High expression, tumor-specific
• Extracellular epitope
• High affinity binding
• Epitope not internalized
• Epitope not secreted or shed

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Antibody conjugates

• Immunotoxins
• Very potent
• Couples MABs to highly lethal toxins
• Plants (Ricin)
• Bacterial (Pseudomonas Exotoxin)
• Ricin a(toxic) and ß chains
• Replace or block ß chain
• Anti-CD 19 and anti-CD 22 Mab conjugates to Ricin
  in the ttt of B-cell lymphoma

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MABS IN LEUKEMIA/ MYELOMA

• LEUKEMIAS
• Radiolabeled anti-CD33 and anti-CD45
• anti-CD38 AND anti-CD64
• Anti-idiotype antibody, anti-CD19, anti-CD54
• MYELOMA
• Anti-CD19, Anti-CD138, Anti-CD54
• Anti-CD20 with interferon gamma

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ANTIBODY-INDUCED BIOLOGICAL RESPONSES

• Direct Anti-tumor effect
• Apoptosis/ligand-receptor interference/ prevent
  protein expression
• Anti-idiotype network induction
• Complement mediated cytotoxicity
• Antibody-directed cellular cytotoxicity (ADCC).

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RITUXIMAB

• CD20 antigen is an attractive target, given its
  stable, high-level surface expression on normal
  and malignant B-cells.
• CD20 297 AA phosphoprotein
• Tightly held in the cell membrane.
• gt 100,000 sites/cell in many B-cell lymphomas
• Follicular
• Mantle
• HCL
• Large cell NHL
• Antigen loss variants are very rare
• Lower density in CLL/SLL

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• No known natural ligand or function
• Expression restricted to B cell with minimal
  expression on pre B-cells and plasma cells.
• RITUXIMAB is a chimeric Anti-CD20 MAb Variable
  regions of CD20-binding murine IgG1 MAb and human
  IgG1 ? constant
• Long serum half life
• lt 1 HAMA REACTIONS
• Mechanism of action IN VITRO/ INVIVO

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• FDA approved for relapsed/refractory CD20
  positive B-cell Low-grade/ follicular NHL
• Outpatient IV. weekly 4-8 weeks
• Large multicenter trial (N166)
• - Overall response rate 48 ( 6 complete and 42
  partial response)
• - Median duration of response 11.6 mo.
• 40 response rate on retreatment
• - Effective even in bulky disease
• Combination therapy with interferon/CHOP/Radioimmu
  notherapy.

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Other promising MABS

• Anti-CD52(Campath-1H) monoclonal Ab
• CD52 is present on most normal and malignant
  mature B and T lymphocytes and monocytes/ not on
  Stem cells.
• 500,000 copies/cell
• CDC AND ADCC
• T-Cell PLL/ B-Cell CLL resistant to chemotherapy

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Impediments to MAB therapy

• Distribution/delivery to tumor site
• Poor tumor trafficking of cytotoxic/immunomodulati
  ng cells
• Antigenic heterogeneity
• Shed/internalized antigens
• Human anti-mouse antibody reactions

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• RADIONUCLIDES USED
• FOR RADIOIMMUNOTHERAPY
• Radionuclide Decay Mode Half-life Range
  in tissues(mm)
• 67Cu ß, ?
  62 hrs 2.2
• 177 Lu ß, ?
  6.7 hrs 2.2
• 131 I ß, ?
  8.0 days 2.4
• 90 Y ß
  64 hrs 11.9
• 212 Bi a, ß
  1 hr 0.09
• 125 I Auger electrons
  Nuclear/Perinuclear.

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Implications for laboratory medicine

• FLOW CYTOMETRY
• Negative immunophenotypic studies
• Artifactual vs. real
• Knowledge of MAB dosage and kinetics
• Correlation with immunohistochemistry
• Safety concerns with circulating
  radioimmunoconjugates
• Molecular Diagnostics
• Minimal residual disease APL/ follicular NHL

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