16. Leukemia Cytochemistry Flashcards

1
Q

Neoplasm

A
  • “new growth”
  • Result of unregulated proliferation of a single transformed cell
  • benign or malignant
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2
Q

Leukemia

A
  • Malignant bone marrow neoplasm

- Abnormal cells are present in both the bone marrow and the peripheral circulation

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3
Q

Myeloid

A
  • granulocytes (neutrophils, eosinophils, basophils)
  • monocytes
  • erythrocytes (RBC)
  • platelets
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4
Q

ACUTE LEUKEMIAS

A
  • Abrupt onset
  • Death in weeks or months if not treated
  • All ages affected
    Blasts > 30% (FAB) > 20% (WHO)
  • WBC counts-inc(50%), nl(25%), dec(25%)
  • Anemia, neutropenia, and thrombocytopenia
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5
Q

CHRONIC LEUKEMIAS

A
  • Insidious onset
  • Mostly adults
  • More mature cells
  • Death in years usually
  • WBC count usually very elevated
  • Organomegaly-extramedullary hematopoiesis
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6
Q

Leukemia – Most Common Age Group

A
  • ALL-children
  • CLL-older adults
  • CML-young to middle age adults
  • AML-infants50 years of age
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7
Q

Chromosomal Abnormalities

A

Oncogenes

  • Genes that are associated with dominant-acting cancer mutations
  • Transforms cells into a malignant phenotype

Tumor supressor genes

  • Code for protein that resist malignant transformation
  • Loss is associated with malignancies
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8
Q

Leukemia Affect on Molecular Pathways

A
  • Arrested differentiation
    • t(15:17) found in acute promyelocytic leukemia
  • Transcriptional repression
  • Disruptions of cell signaling
    • BCR-ABL fusion gene in chronic myeloproliferative neoplasms
  • Progression
  • Apoptosis
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9
Q

Hereditary Abnormalities Genetic Susceptibility

A

Associated with abnormal chromosome number or chromosomal instability

    • Down’s syndrome - 20x increase risk of leukemia
    • Kleinfelter syndrome
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10
Q

Environmental Factors

of Leukemia

A
  • Radiation exposure: nuclear reactions, therapeutic radiation, occupational exposure
  • Drugs
  • Chemicals: Chloramphenicol, Arsenic, Insecticides, Benzene
  • Viruses: Retro viruses
    [HTLV-I, II, V (Human T-Cell Leukemia/ lymphoma virus
    HIV-1 (Human Immunodeficiency Virus)], EBV – Burkitts Lymphoma
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11
Q

Clinical Findings

of Leukemia

A
  • Anemia: fatigue, pallor
  • Granulocytopenia: fever, infection
  • Thrombocytopenia: bruising, bleeding
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12
Q

Examples of Laboratory Evaluation for Leukemia

A
  • CBC
  • Peripheral blood smear
  • Bone marrow aspirate/biopsy
  • Cytochemistry
  • Flow cytometry (Immunophenotyping)
  • Cytogenetics
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13
Q

CDC of Leukemia

A
  • Anemia: mild to severe, normocytic, normochromic
  • Platelet counts: decreased
  • WBC - variable
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14
Q

Peripheral Smear of Leukemia

A
  • MAY reveal blasts or other immature cells
  • Circulating nRBC
  • Other dysplastic features: Hypogranlation,
    Pelger Huet cells (hyposegmentation)
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15
Q

Bone Marrow Aspirate/Biopsy

A
  • Presence of blasts (%)
  • Morphology
  • Cellularity, other elements (is there a 3:1 ratio?)
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16
Q

Immunophenotyping

A
  • Immunologic technique using monoclonal antibodies to identify Antigens on cells.
  • An International team designed a nomenclature system for Antibodies that have the same specificity (Cluster of Designation). Each cluster is assigned a number.[Example (CD 33, CD 34) etc….]
17
Q

Cytogenetics

A
  • looking at chromosome, DNA, karyotype

Involved in:

  • Diagnosis
  • Classification
  • Prognosis
  • Treatment
18
Q

Cytochemistry

A
  • The in vitro staining of cells that allows microscopic examination of the cell’s chemical composition
  • Help to differentiate the lineage of immature cells
19
Q

Cytochemical Stain

A
  • Cells are incubated with substrates that react with specific chemical constituents
  • If the specific constituent is present, it’s reaction is confirmed by the formation of a colored product within the cell
  • Samples : Peripheral blood film, Bone marrow aspirate, Biopsy touch preps
20
Q

Sudan Black B

A
  • Stains lipids, phospholipids, neutral fats, sterols
  • Granulocytes: membranes of both primary and secondary granules stain intensely
  • Auer rods +++
  • Monocytes – weakly positive
  • Lymphocytes - negative
  • Used to differentiate AML from ALL
21
Q

Myeloperoxidase Stain

A
  • similar to SBB
  • Identifies the sites of myeloperoxidase activity
  • Granulocytes intensely positive
  • Monocytes weakly positive
  • Lymphocytes negative
  • Used to differentiate AML from ALL
22
Q

Chloroacetate (specific) esterase

A
  • similar to SBB and MPO
  • Identifies site of chloroacetate esterase activity
  • Specific for granulocytic series
  • Monocytic series negative to weakly positive
  • Lymphocytic cells are negative
  • Differentiates AML from ALL
23
Q

Alpha naphthol (non-specific) esterase stain

A
  • Identifies alpha naphthol esterase activity primarily in monocytes
  • Very weak or absent activity in granulocytes, megakaryocytes, lymphocytes
  • Used to diagnose Myelomonocytic (M4) and Monocytic (M5) leukemias
24
Q

Periodic Acid-Schiff (PAS) Stain

A
  • Stains glycogen and glycols in mature granulocytes, platelets, megakaryocytes and monocytes
  • Early myeloid cells are negative
  • Normal erythroid precursors are negative
  • M6 erythroblasts stain positive
  • ALL lymphoblasts may have coarse block-like positivity
25
Q

Leukocyte Alkaline Phosphatase Stain (NAP)

A
  • aka Neutophil Alkaline Phosphatase Stain (NAP)
  • Identifies enzyme activity in secondary granules of mature neutrophils (beginning at the metamyelocyte stage)
  • Not present in eosinophils or basophils
  • Positivity is scored 0 – 4+
  • Used to differentiate CML from Leukemoid Reaction

NAP Scores:

  • Normal – approx 50-150
  • Decreased – CML, PNH
  • Increased – Leukemoid Reaction (severe infection), Polycythemia Vera
26
Q

Acid Phosphatase Stain

A
  • Most cells have some activity

- Hairy cells are strongly positive and not inhibited by tartrate = TRAP positive (Tartrate resistant)

27
Q

Terminal Deoxynucleotidyl Transferase (TdT)

A
  • Rabbit anti-TdT + Goat anti-rabbit-FITC
  • Look for nuclear fluorescence
  • Marker for immature lymphocytes
  • No peripheral blood cells positive normally
28
Q

Factor VIII Stain

A
  • Immunocytochemical stain that gives positive results in megakaryoblastic leukemias
  • Uses antibodies directed against Factor VIII contained in platelet precursors
  • Some labs use antibodies against platelet glycoproteins
29
Q

Acute Megakaryocytic Leukemia

A
  • Immunoperoxidase staining (brown) for Factor VIII related protein identifies the blasts as being of megakaryocyte lineage
30
Q

Treatments of Leukemia

A
  • Chemotherapy
  • Radiation therapy
  • Targeted therapy: Monoclonal antibodies target specific antigens on malignant cells
  • Stem Cell Transplantation