88 Chronic Myelogenous Leukemia and Related Disorders Flashcards
The translocation between chromosomes 9 and 22 in more than _______% of patients
90%
Leads to an overtly foreshortened long arm of one of the pair of chromosome 22 (ie, 22,22q−), referred to as the Philadelphia chromosome (Ph)
ABL1 gene on chromosome 9 and the BCR gene on chromosome 22
The breaks at chromosomes 9 and 22 were localized to
Band 34 on the long arm of chromosome 9 and band 11 on the long arm of chromosome 22
What are environmental leukemogens associated with CML
- Very high doses of ionizing radiation
- Radioactive iodine for thyroid cancer
- Smoking
- Chemotherapy administered for germ cell tumors
- Chemical leukemogens, such as benzene and alkylating agents, are not causative agents of CML
- CML does not generally arise as a secondary malignancy.
Three main BCRs have been characterized on chromosome 22:
major (M-bcr): p210p
minor (m-bcr): p190
micro (μ-bcr): p230
Majority of CML patients have a BCR-ABL1 fusion gene that encodes a fusion protein of
p210BCR-ABL1
e14a2 or e13a2
50% of the Ph-positive acute lymphoblastic leukemia cases and results in the production of a
BCR-ABL1 protein of 190 kDa (p190BCR-ABL)
e1a2
Breakpoints develop a CML blast crisis with monocytosis and an absence of splenomegaly and basophilia
CML patients with m-bcr breakpoints
Breakpoint associated with neutrophilic CML or thrombocytosis
p230
e19a2
Perivascular infiltrate of neutrophils in the dermis
Fever accompanied by painful maculonodular violaceous lesions on the trunk, arms, legs, and face
Acute febrile neutrophilic dermatosis
(Sweet syndrome)
Most common blood cell at time of diagnosis
Segmented forms
Features of CML in child hood and young adolescents
- Hyperleukocytosis
- Increased frequency of splenomegaly and greater spleen size
- Lower rates of disease response to TKIs
- Higher rates of transformation
Neutrophil alkaline phosphatase activity is___________ in more than 90% of patients with CML.
Low or absent
Designation when eosinophils are so prominent that they dominate the granulocytic cells
Ph-positive eosinophilic CML
An absolute increase in the___________ concentration is present in almost all patients, and this finding can be useful in preliminary consideration of the differential diagnosis
Basophil
The proportion of basophils usually is not greater than______ during the chronic phase
15%
May represent 30% to 80% of the total leukocyte count during chronic phase and lead to the designation of Ph-positive basophilic CML.
Flow cytometry using __________ provides very accurate assessment of the basophil frequency.
anti-CD203c
Granules of basophils in patients with CML, unlike normal basophils, contain mast cell α-tryptase.
TRUE or FALSE
The total absolute lymphocyte count is increased (mean: approximately 15 × 109/L) in patients with CML
TRUE
The total absolute lymphocyte count is increased (mean: approximately 15 × 109/L) in patients with CML
As a result of the balanced increase in T-helper and T-suppressor cells.
- B lymphocytes are not increased.
- T lymphocytes are increased in the spleen.
- NK cell activity is defective in CML patients as a result of decreased maturation of these cells in vivo.
TRUE or FALSE
The platelet count is elevated in all of patients at the time of diagnosis.
FALSE
The platelet count is elevated in approximately 50% of patients at the time of diagnosis and is normal in most of the rest.
Occasionally, the platelet count may be below normal (<150 × 109/L) at the time of diagnosis, but this finding usually signals an impending progression to the accelerated phase of the disease and may also occur with massive splenomegaly.
BMA features of CML
- Markedly hypercellular and hematopoietic tissue takes up 75% to 90% of the marrow volume
- Granulopoiesis is dominant, with a granulocytic-to-erythroid ratio between 10:1 and 30:1
- Erythropoiesis usually is decreased, and megakaryocytes are normal or increased
- Eosinophils and basophils may be increased
- Collagen type III (reticulin fibrosis), which takes the silver impregnation stain, is increased at the time of diagnosis in nearly half the patients, and is correlated with the proportion of megakaryocytes in the marrow.
- Doubling of microvessel density and have more angiogenesis
Increased fibrosis also is correlated with larger spleen size, more severe anemia, and a higher proportion of marrow and blood blast cells.
The Ph chromosome is present in all blood cell lineages except in
B lymphocytes or in most T lymphocytes
TRUE OR FALSE
Interphase FISH is faster and more sensitive than cytogenetics in identifying the Ph chromosome.
TRUE
Interphase FISH is faster and more sensitive than cytogenetics in identifying the Ph chromosome.
The method of choice for monitoring patients for residual disease or reappearance of disease after marrow transplantation and for following response to TKIs
Quantitative RT-PCR
A complete cytogenetic response (CCyR) is equivalent to a negative FISH test and BCR-ABL1 transcripts ______
<1%
Patients with myeloproliferative neoplasms have an_________ serum level of vitamin B12–binding capacity, and the source of the protein is principally mature neutrophilic granulocytes
Increased
Spurious increase or decrease associated with CML
Pseudohyperkalemia
Spurious hypoxemia
Pseudohypoglycemia
In CML, LDH is (decreased/elevated) while cholesterol is (decreased/elevated)
In CML, LDH is elevated while cholesterol is decreased
TRUE OR FALSE
Elevated serum and urinary lysozyme levels are features of leukemia with greater monocytic components and are not features of CML.
TRUE
Elevated serum and urinary lysozyme levels are features of leukemia with greater monocytic components and are not features of CML
Characteristic of NEUTROPHILIC CHRONIC MYELOGENOUS LEUKEMIA
- Composed principally of mature neutrophils
- The white cell count is lower (30–50 × 109/L) at the time of diagnosis
- Do not have basophilia
- Have an unusual BCR-ABL1 fusion gene in that the breakpoint in the BCR gene is between exons 19 and 20–> larger fusion protein (230 kDa)
Characteristic of MINOR-BCR BREAKPOINT–POSITIVE CHRONIC MYELOGENOUS LEUKEMIA
- Result in a 190-kDa fusion protein
- Monocytes are more prominent
- White cell count is lower
- Basophilia and splenomegaly are less prominent
Observed in approximately 60% of patients with BCR rearrangement-positive ALL
Hyperleukocytosis may occur when white cell counts greater than ______
300 × 109/L
If signs of hyperleukocytosis are present,hydration, leukapheresis, and hydroxyurea can be used simultaneously
Management of hyperurecemia in CML
- Adequate hydration
- Allopurinol (Zyloprim) 300 mg/day orally
- Rasburicase (Elitek)
- Rasburicase is a recombinant urate oxidase that converts uric acid to allantoin.
- Reduces the uric acid pool very rapidly, does not result in the accumulation of xanthine or hypoxanthine, and does not require alkalinization of urine, thus facilitating phosphate excretion
Leukapheresis is useful in only 2 types of patients:
- The hyperleukocytic patient in whom rapid cytoreduction can reverse symptoms and signs of leukostasis (eg, stupor, hypoxia, tinnitus, papilledema, priapism) and
- The pregnant patient with CML who can be controlled by leukapheresis treatment without other therapy either during the early months of pregnancy when therapy poses a higher risk to the fetus or, in some cases, throughout the pregnancy
Dose of Hydroxyurea for cytoreduction
1–6 g/day orally
- Should be decreased as the total white cell count decreases and usually is given at 1–2 g/day when the total white cell count reaches 20 × 109/L
- The drug should be temporarily discontinued if the white cell count drops below 5 × 109/L.
Given in patients who still have significant thrombocythemia after a TKI is initiated
Anagrelide
Types of TKI
First generation
* Imatinib (Gleevec)
Second generation
* Nilotinib (Tasigna)
* Dasatinib (Sprycel)
Third generation
* Bosutinib (Bosulif)
* Ponatinib (Iclusig)
- Imatinib: first TKI developed
- An overall survival (OS) advantage of dasatinib, nilotinib, or bosutinib compared with imatinib has not been shown.
- Ponatinib (Iclusig) is not yet approved for initial therapy
TKI that can be given to CML BP
- Imatinib
- Dasatinib
- Bosutinib
TKI for Ph+ ALL
- Imatinib
- Dasatinib
- Ponatinib
TKI approved in children with CML
Imatinib
TKI for T315I+ cases
Ponatinib
Dosing of TKI
Imatinib
* CP 400 mg/day
* AP/BP/progression 600–800 mg/day
Nilotinib
* CP 300 mg BID
* AP/BP 400 mg BID
Dasatinib
* CP 100 mg/day
* AP/BP 140 mg/day
Bosutinib
* 500 mg/day
Ponatinib
* 45 mg/day
Toxicities of TKI
- Muscle cramps, arthralgia
- Elevated LFTs (usually appear in first month)
- Severe periorbital edema
- Hair depigmentation and hypopigmentation of the skin
- Rare cardiac toxicity reported
Imatinib
Toxicities of TKI
- Elevated lipase, hyperglycemia
- Peripheral vascular disease
- PT prolongation
Nilotinib
Toxicities of TKI
- Pleural effusions, ascites and pericardial effusion
- Pulmonary arterial hypertension
- QTc prolongation
- Bleeding from inhibition of platelet aggregation
Dasatinib
Toxicities of TKI
- GI (diarrhea)
Bosutinib
Toxicities of TKI
- High blood pressure
- Headache
- Arterial and venous thrombosis
- Ocular toxicity
- Cardiac failure
Ponatinib
TKI with significant interactions with antacids, H2 antagonists, proton pump inhibitors
Dasatinib
Bosutinib
decrease levels
Administration of TKI
With food:
Without food:
With or without food:
With food: Imatinib, Bosutnib
Without food: Nilotinib
With or without food: Dasatinib, Ponatinib
Black box warnings for TKI
Nilotinib:
Ponatinib:
Nilotinib: QT prolongation and sudden death
Ponatinib: Arterial thrombosis; hepatotoxicity