Hematology 425 Leukocyte Neoplasms

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Hematology 425 Leukocyte Neoplasms

• Russ Morrison
• November 29, 2006

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Leukocyte Neoplasms

• Neoplasm is defined as an abnormal tissue that
  grows by cellular proliferation more rapidly than
  normal and continues to grow after the stimuli
  that initiated the new growth ceases
• A neoplasm may be benign as with a tumor or
  malignant in cancer(s)
  
• A leukocyte neoplasm is abnormal cellular
  proliferation in the WBC series

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Leukocyte Neoplasms

• Leukemias are a group of diseases manifested by
  malignant, unregulated proliferation of cells
  normally found in the bone marrow
  
• Leukemia may involve any of the blood-forming
  cells or their precursors
  
• Leukemia may be found in metastatic lesions
  throughout the body, in the brain, liver, spleen
  and lymph nodes

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Leukocyte Neoplasms

• Though leukemias progress differently, the
  unregulated proliferating cells have four things
  in common
  
• They usually replace normal marrow
• They eventually interfere with normal marrow
  function
  
• They may invade other organs
• The eventually cause death if they go untreated

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Leukocyte Neoplasms

• Leukemias are relatively new diseases since they
  were first described in 1845
  
• In 1900, it was reported that acute and chronic
  leukemias involve different types of WBCs
  
• In chronic leukemias, mature cells are
  predominant while in acute leukemias, immature
  cells (blasts) hold center stage

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Leukocyte Neoplasms

• Since the 1900s, leukemias have been studied with
  the microscope, cytochemical stains, electron
  microscopy, immunologic nuclear and surface
  markers and cytogenetic techniques
• Standardized subclassification of leukemia
  subtypes leads to better treatments through
  pharmaceutical research
  
• Today, we are at a threshold of development of
  targeted therapies, better treatments and cures
  for both the acute and chronic leukemias

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Clinical Classification of Leukemia

• Leukemias are divided into acute and chronic
  diseases based on their presenting signs and
  symptoms as well as the cell type involved
  
• Acute leukemias are characterized by abrupt onset
  of clinical signs (infection, hemorrhage and
  pallor) and symptoms (fatigue, weakness, bone and
  joint pain)
• Death occurs within months in acute leukemia if
  treatment is not begun

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Clinical Classification of Leukemia

• WHO classification of acute leukemias requires a
  minimum of 20 blast forms (myeloid or lymphoid)
  in either the PB or BM
  
• PB WBC counts may be increased, decreased or
  normal, though typically they are increased
  
• Normocytic anemia and neutropenia are classic
  states, while thrombocytopenia is usually present

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Clinical Classification of Leukemia

• Chronic leukemias have an insidious onset of
  signs (pallor, splenomegaly and/or hepatomegaly,
  weight loss) and symptoms (weakness, fatigue,
  depression)
• They usually occur in adults and death occurs
  years after diagnosis
  
• WBC counts are variable, though usually higher
  than seen in acute leukemia and cell forms are
  more mature
  
• Platelet counts are normal or increased
• Acute vs Chronic is compared in Table 32-1

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Classification by Cell Type

• A PB smear can initiate a diagnosis of acute or
  chronic leukemia
  
• Additional information is gathered to
  subcategorize the lymphocytes in CLL and some of
  the CMLs using cytochemistry, flow cytometry, PCR
  and cytogenetics
• Genetic testing to determine specific gene
  abnormalities will become standard within the
  next few years

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Morphologic identification of Lymphoblasts vs
myeloblasts

• Lymphoblast
• 2-3 times the size of a normal lymphocyte
• Have scant blue cytoplasm
• Uniform coarse chromatin
• Inconspicuous nucleoli

• Myeloblast
• 3-5 times the size of a normal lymphocyte
• Moderate grey cytoplasm
• Uniform fine chromatin
• 2 or more prominent nucleoli
• Auer rods

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ALL
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AML (note Auer Rod)
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Morphologic Subtypes of ALL

• Three morphologic subtypes of blasts have been
  described according to the FAB classification
  system
  
• Little, if any, prognostic information is gained
  from this classification
  
• Subtypes are termed L1, L2 and L3 based on the
  following descriptions

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ALL L1 Lymphoblasts

• Small
• Scant blue cytoplasm
• Round nuclei
• Indistinct nucleoli
• The most common type of ALL

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ALL L1 Lymphoblasts
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ALL L2 Lymphoblasts

• 2-3 times the size of a normal lymphocyte
• Moderate cytoplasm
• Irregular nuclear membrane
• Prominent nucleoli
• May resemble AML

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ALL L2 Lymphoblasts
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ALL L3 Lymphoblasts

• Large
• Midnight blue cytoplasm
• Cytoplasmic vacuoles are present
• 3-5 nucleoli

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ALL L3 Lymphoblasts
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Other Classifications of Acute Leukemias -
Cytochemical

• Cytochemical staining classification systems were
  developed by FAB
  
• The current panel of stains includes
  myeloperoxidase, Sudan black B, chloroacetate
  esterase, and nonspecific esterase
  
• Table 32-2 shows the FAB classification of acute
  leukemias by cytochemical reactions

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Other Classifications of Acute Leukemias -
immunologic

• Monoclonal antibodies and flow cytometry added to
  morphology and cytochemical stains brings the
  accuracy of identification of leukemic cell lines
  to 95
• The technique is more commonly used for lymphoid
  rather than myelogenous cell lines
  
• A panel of cell line markers is used because no
  single surface marker is specific
  
• Table 32-3 shows the immunologic classification
  of these cells

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Other Classifications of Acute Leukemias -
Cytogenetic

• Chromosomal alterations aree associated with
  leukemic cells
  
• Cytogenetic studies can be used to detect clonal
  abnormalities
  
• Clonal abnormalities can be of number (ploidy) or
  of structure (translocations, deletions and
  rearrangements)

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Other Classifications of Acute Leukemias -
Molecular

• Molecular Diagnostics/PCR are able to identify
  genetic mutations in both acute and chronic
  leukemias
  
• As these methods develop, the diagnosis and
  classification of acute and chronic leukemias
  will be performed by molecular methods

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Acute Leukemias - ALL

• Acute lymphoblastic leukemia (ALL) is a disease
  of childhood
  
• Most cases occur between the ages of 2 and 10
  years of age
  
• All is rare in adults, but a second cluster of
  incidence occurs among elderly patients
  
• Treatment of childhood ALL now yields a 90 rate
  of complete remission with a 60 cure rate

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Acute Leukemias - ALL

• Adults with ALL do not fare as well having a
  68-91 remission rate and a 25-41 cure rate
  
• Approximately half of patients with ALL have
  increased WBC counts and they may or may not have
  lymphoblasts in the PB
  
• Neutropenia, thrombocytopenia and anemia are
  usually present
  
• This pancytopenia causes fatigue, fever and
  bleeding and there is often lymph node enlargement

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Acute Leukemias - ALL

• Hepatomegaly and splenomegaly are often present
  as well as bone pain due to infiltration of
  leukemic cells into the periosteum
  
• Eventually, the meninges are invaded by malignant
  cells and lymphoblasts are found in the CSF
  
• Lymphoblast infiltration into the testes and
  ovaries is common, especially in relapse

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ALL - Prognosis

• Prognosis is dependent on the age of the patient
  at the time of diatnosis
  
• It is also related to the lymphoblast load and
  immunophenotype
  
• Chromosomal translocations (ex Philadelphia
  Chromosome 5(922)) are proving to be a strong
  predictor of adverse treatment outcomes for both
  children and adults

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ALL - Prognosis

• Patients 2-10 years of age have the best
  prognosis
  
• Children less than 1 year of age do poorly
• Children between 1 and 2 have an intermediate
  success rate, as do teenagers and young adults
  
• Lymphoblast count 20-30 x109/L,
  hepatosplenomegaly and lymphadenopathy all
  decrease the effectiveness of treatment and the
  patients are considered high risk

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ALL - Prognosis

• Other variables showing decreased outcomes
  include race (native American), karyotypic
  abnormalities and sex (male)
  
• Morphology
• The three major FAB classifications FAB-L1,
  FAB-L2, and FAB-L3 were discussed in Chapter 32

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ALL - Immunophenotyping

• Morphology is the first tool in distinguishing
  ALL from AML, but immunophenotyping is the best
  indicator of a cells origin
  
• Immunologic classification of ALL should be
  performed in all cases due to the prognostic
  implications

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ALL - Treatment

• Success with treatment is divided by age of
  presentation
  
• Intrathecal methotrexate is used with children
• Methotrexate is a folate antagonist and kids on
  this drug will be megaloblastoid
  
• Adults are treated with daunorubicin, vincristine
  and prednisone (all with side effects)
  
• Stem cell or bone marrow transplantation is the
  last line of treatment for unresponsive or
  relapsed ALL

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Acute Myeloid Leukemia - AML

• AML is the most common leukemia in children less
  than 1 year of age
  
• AML is rare in older children and adolescents
• A second age focus of AML occurs among adults 40
  years of age
  
• AML is rapidly fatal if not treated
• 8 types of AML (M0 thru M7) have been described

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AML Clinical Presentation

• Clinical presentation is nonspecific reflecting
  the decreased production of normal BM elements
  
• WBC count is usually between 5000 and 30,000/mm3,
  but may be as high as 200,000 or as low as 1000
  
• Myeloblasts are present in the PB of 90 of
  patients
  
• Anemia, thrombocytopenia and neutropenia lead to
  symptoms of pallor, fatigue, bruising, bleeding
  and fever with infections

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AML Clinical Presentation

• DIC and other bleeding abnormalities occur,
  especially with M3-promyelocytic and monocytic-M5
  forms of AML
  
• Infiltration of malignant cells into the gums and
  mucous membranes, as well as the skin are is seen
  in M4-myelomonocytic and M5-monocytic types
  
• Bone and joint pain is the first symptom in 25
  of patients
  
• Splenomegaly is seen in half of AML patients, but
  lymph node enlargement is rare

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AML Clinical Presentation

• AML patients do not usually exhibit symptoms when
  the CNS is infiltrated with blasts
  
• Elevated uric acid, potassium and phosphate
  levels along with decreased calcium (termed
  tumor-lysis syndrome), renal failure, tetany and
  lethal heart arrythmias may develop

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AML Subtypes

• Micrographs of the AML subtypes are exhibited in
  the text and atlas
  
• The FAB cooperative group has defined 8 subtypes
  (M0-M8) of AML based on bone marrow morphology
  and cytochemical reactions
  
• In the FAB classification, 2 types of myeloblasts
  have been described
  
• Type 1 have typical blast morphology and no
  azurophilic granules
  
• Type 2 may contain a small number of primary
  granules

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AML Subtype M0

• Acute myeloblastic leukemia, minimally
  differentiated
  
• Blasts do not display morphologic myeloid
  characteristics
  
• Fewer than 3 of blasts exhibit myeloperoxidase
  or Sudan black B positivity
  
• Auer rods are not sen
• May express antigen TdT

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AML Subtype M1

• Acute myeloblastic leukemia, without maturation
• Displays minimal myeloid differentiation
• Myeloblasts constitute more than 30 of the BM
  nucleated cells
  
• ME ratio is greater than 1
• 90 of the erythroid cells are myeloblasts
• 3 of the myeloblasts show positivity when
  stained with myeloperoxidse of Sudan black B
  
• Easily confused with ALL (L2 type)
• Accounts for 20 of cases of AML

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AML Subtype M2

• Acute myeloblastic leukemia, with maturation
• 30 of nucleated cells must be blasts in the BM
  film and myeloid cells outnumber NRBCs
  
• Blasts constitute fewer than 90 of nonerythroid
  cells and there is maturation beyond the
  promelycyte in more than 10 of nonerythroid
  cells
• Majority of blasts stin positively when stained
  with myeloperoxidase or Sudan black B
  
• Subtype accounts for 30 of cases of AML

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AML

• Induction therapy in M1 and M2 leukemia is
  usually effective, resulting in sufficient return
  of normal marrow responses for an autologous bone
  marrow transplant
• Drugs frequently used are daunorubicin and
  cytosine arabinoside
  
• Cardiac monitoring is necessary due to side
  effects
  
• Cytosine arabinoside is active against the
  nucleus, resulting in a megaloblastoid
  presentation of the CBC

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AML Subtype M3

• Acute promyelocytic leukemia
• May be one of two types, hypergranular or
  microgranular
  
• Stain strongly positive with myeloperoxidase
• M3 patients must be recognized because bleeding
  problems (DIC) occur when these patients are
  treated and the granules are released
  
• Make up approximately 15 of all AML cases
• Treatment with all-trans retinoic acid (ATRA) a
  form of Vitamin A causes the cells to undergo
  maturation (cells have a defective vitamin A
  receptor)

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AML Subtype M4

• Acute myelomonocytic leukemia
• Has malignant cells with both granulocytic and
  monocytic features
  
• BM more than 30 of nucleated cells are blasts
• When the ME ratio is greater than 1, more than
  20 of nonerythroid cells are monocytic
  
• A small percent has moderate eosinophilia
  (AML-M4Eo), have CSF involvement and a better
  remission rate and response to chemotherapy

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AML Subtype M5

• Acute monocytic leukemia
• Accounts for 12 of AML
• Diagnosis based solely on the BM morphology
• More than 30 of cells are blasts
• More than 80 of cells are monocytic, less than
  20 granulocytic
  
• Two subtypes recognized, M5a and M5b
• Skin involvemen and gum infiltration may be seen
  in both types

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AML M5 Gum infiltration
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AML Subtype M6

• Acute erythroleukemia
• Rare, 3 of AML cases
• The only AML with hyperplasia of erythroid
  precursors

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AML Subtype M7

• Acute megakaryocytic leukemia
• The rarest type of AML at
• In adults, many cases are preceded by a
  myeloproliferative disorder with pancytopenia or
  myelofibrosis
  
• In children it is more frequent among patients
  under three years of age with Down syndrome
  
• Response to therapy is poor

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Other Acute Myeloid-like Leukemias

• Acute undifferentiated leukemia and hybrid
  leukemias are often treated as AML, but are not
  necessarily related
  
• Undifferentiated acute leukemia is a rare
  disorder in which the lineage of the blasts can
  not be determined
  
• Hybrid leukemias are leukemias with both lymphoid
  and myeloid characteristics

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Chronic leukemias lymphocytic disorders

• There are two major types of chronic lymphoid
  leukemias
  
• Chronic lymphocytic leukemia (CLL)
• Hairy cell leukemia
• There are also a few other forms of chronic
  lymphoid leukemias that are rare and not
  discussed in this series

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Chronic Lymphocytic Leukemia

• CLL is the most common type of leukemia
• Usually occurs in older patients
• Most commonly found in patients older than 40
  (though youngest case was 22)
  
• Affects twice as many men as women
• No specific chromosomal abnormality has been
  associated with CLL

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CLL Clinical Course

• Variable clinical course with most patients
  living at least 1-2 years after diagnosis
  
• Median survival is 6 years and some patients live
  many years with the disease and die of other
  causes
  
• It is impossible to tell at the time of diagnosis
  what the estimated life span will be
  
• CLL is often discovered when other medical
  problems such as persistent viral infection are
  being investigated

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CLL Clinical Course

• When symptoms are present, they are usually
  nonspecific, such as weakness, fatigue, weight
  loss
  
• Lymphadenopathy and marked hepato-splenomegaly
  are frequent, especially late in the disease
  
• The malignant cell in CLL is usually a small,
  mature-appearing lymphocyte with B-cell
  immunophenotype
  
• Smudge cells are seen in the PB

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CLL Clinical Course

• Diagnosis of CLL depends on sustained lymphocyte
  count greater than 10 x 109/L
  
• Other causes of lymphocytosis must be ruled out
• Subsets of lymphocytes cannot be differentiated
  by morphology
  
• Phenotyping using flow cytometry is a good method
  to identify clonal expansion
  
• 2 staging systems are used for CLL and are
  presented in table 34-2 (RAI and Binet)

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CLL Clinical Course

• Anemia and thrombocytopenia usually appear late
  in the course of the disease
  
• CLL is often associated with autoimmune
  phenomena
  
• AIHA occurs in 15-35 of patients
• CLL may remain stable or undergo morphologic
  transformation
  
• Patients who have experienced morphologic
  transformation are less responsive to treatment

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CLL Clinical Course

• Initial treatment of CLL involves a
  watch-and-wait approach
  
• Eventual treatment of the disease can range from
  conservative (leukophorresis) to traditional
  chemotherapy (cytosine arabinoside) to aggressive
  (bone marrow transplantation) to designer drugs
  (anti-CD20)

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CLL - PB
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Hairy Cell Leukemia

• A rare malignant disorder accounting for 2 of
  all leukemias
  
• Usually occurs in middle-aged patients with a
  median age of 50 years
  
• Has an insidious onset characterized by weakness
  and lethargy
  
• Splenomegaly is present in 80 of patients
• Pancytopenia is characteristic and BM aspirates
  result in a dry tap

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Hairy Cell Leukemia

• Hairy cells have reniform to oval nuclei with
  finely granular chromatin and delicate gray
  cytoplasm with projections that give the cell a
  hairy appearance
• Immunologically, the hairy cell is a mid- to late
  B cell
  
• Patients may live for many years with the
  disease median length of survival is 7 years

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Hairy Cell Leukemia
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Other Chronic Leukemias of Lymphoid Origin

• Other B-Lymohoid chronic leukemias include
• Prolymphocytic leukemia
• Waldenstrom macroglobulinemia
• Lymphosarcoma cell leukemia
• Chronic leukemias of T-cell origin are rare and
  comprise

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Chronic Myelogenous Leukemia

• CML is considered a chronic myeloproliferative
  disorder and is characterized by panmyelosis with
  a predominance of myeloid component in the BM, PB
  and other organs
• Occurs at any age, but most commonly after 45
  years of age
  
• Weight loss and fatige are the initial symptoms
• Massive splenomegaly may cause left upper
  abdominal pain or gastric discomfort

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CML

• Anemia is present, markedly elevelated WBC counts
  (50-500 x 109/L or higher)
  
• Thrombocytosis, eosinophilia, basophilia and a
  range of granulocyte maturation with a
  predominance of myelocytes is seen in the PB
  
• Myeloblasts constitute fewer than 10 of
  circulating leukocytes
  
• Occasional NRBCs are seen and the PB resembles a
  BM aspirate

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CML

• Pseudo-Pelger-Huet cells, twinning and other
  nuclear abnormalities may be present
  
• The Philadelphia chromosome (a translocation of
  the long arm of C22 to C9 is present in almost
  all cases of CML
  
• Patients with CML usually undergo a chronic phase
  that lasts 3 years called the meridian
  
• This stage can be prolonged using interferon-a
• An accelerated phase follows with worsening
  clinical features that are less responsive to
  therapy

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CML

• Approximately 1/3 of patients enter blast
  crisis in which the disease resembles acute
  leukemia
  
• 1/3 of patients entering blast crisis have ALL
  and 2/3 have AML blast crisis
  
• Treatment consists of trying to keep or return
  the patient to the initial or chronic phase
  
• BM or stem cell transplants have shown some
  promise
  
• Development of a targeted anti-tyrosine kinase
  drug has shown promise in trials

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CML FISH, Philadelphia Chromosome
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CML
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CML
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CML