CML and Myeloproliferative Disorders

Question 1

Normal Hb

Answer 1

135-175

Question 2

Normal heamatocrit

Answer 2

0.41-0.53

Question 3

True polycythaemia

Answer 3

Increased red cell mass

No change in plasma volume

Question 4

Causes of true polycythaemia

Answer 4

Primary polycythaemia vera (reduced EPO) 
Secondary polycythaemia (elevated EPO)

Question 5

Relative (pseudo) polycythaemia

Answer 5

No change in red cell mass

Reduced plasma volume

Question 6

Causes of pesudo polycythaemia

Answer 6

Alcohol
Obesity
Diuretics

Question 7

Causes of true secondary (non-malignant) polycythaemia

Answer 7

Raised erythropoietic can be appropriate or inappropriately raised.

Appropriately: 
High altitude
Hypoxic lung disease 
Cyanotic heart disease
High affinity haemoglobin 

Inappropriate:
Renal disease (cysts, tumours, inflammation)
Uterine myoma
Other tumours (liver, lung)

Question 8

Haematological malignancies

Answer 8

Myeloid

Lymphoid: precursor cell malignancy or mature cell malignancy

Question 9

Myeloid malignancies

Answer 9

Acute myeloid leukaemia (blasts >20%)
Myelodysplasia (blasts 5-19%)
Myeloproliferative disorders: Essential thrombocythaemia (megakaryocyte), Polycythemia vera (erythroid), Primary myeofibrosis
Chronic myeloid leukaemia

Question 10

Lymphoid: precursor cell malignancies

Answer 10

Acute lymphoblastic leukaemia (B & T)

Question 11

Lymphoid: mature cell malignancies

Answer 11

Chronic Lymphocytic leukaemia
Multiple myeloma
Lymphoma (Hodgkin & Non Hodgkin)

Question 12

Myeloproliferative disorders

Answer 12

Ph negative: polycythaemia vera, essential thrombocythaemia, primary myelofibrosis

Ph positive: chronic myeloid leukaemia

Question 13

What processes are disrupted by mutation in blood cell formation

Answer 13

Impair/block cellular differentiation (type 2) 
Cellular proliferation (type 1) 
Prolong cell survival (anti-apoptosis)

Question 14

Mutation mechanisms

Answer 14

DNA point mutations

Chromosomal translocations: Creation of novel Fusion gene, Disruption of proto-oncogene

Question 15

Leukaemia mutations

Answer 15

Cellular proliferation (type 1) –> tyrosine kinase activation

Question 16

Tyrosine kinases

Answer 16

Transmit cell growth signals from surface receptors to nucleus
Activated by transferring phosphate groups to self and downstream proteins
Normally held tightly in inactive state
Promote cell growth do not block maturation

Question 17

Tyrosine kinase mutations

Answer 17

Expansion increase in mature/end cells
Red cells; polycythaemia
Platelets; essential thrombocythaemia
Granulocytes; chronic myeloid leukaemia

Question 18

What gene mutations are associated with myeloproliferative disorders

Answer 18

JAK2
Calreticulin
MPL

Question 19

Polycythaemia vera epidemiology

Answer 19

Annual incidence 2-3/100000
Slightly more in males 1.2:1
Mean age at diagnosis 60 years
5% below age of 40 years

Question 20

Polycythaemia vera clinical presentation

Answer 20

Incidental diagnosis on routine blood testing
Symptoms of increased hyper viscosity: Headaches, light-headedness, stroke, Visual disturbances, Fatigue, dyspnoea

Increased histamine release: Aquagenic pruritus, Peptic ulceration

Question 21

Clinical findings in polycythaemia vera

Answer 21

Variable splenomeagaly 79% of cases
Plethora
Erythromelalgia: red painful extremeties
Thrombosis
Retinal vein engorgement
Gout due to increased red cell turnover and overproduction of uric acid
Absence of other causes of increased haematocrit

Question 22

Principles of treatment of polycythaemia vera

Answer 22

Aim to reduce viscosity as blood viscosity rises expenonentially with rising HCT : keep HCT <45%: Venesection, Cytoreductive therapy for maintenance hydroxycarbamide

Aim to reduce risks of thrombosis: Aspirin, Keep platelets below 400x109/l (same as treatment of essential thrombocythaemia)

Question 23

Essential thrombocythaemia

Answer 23

Chronic MPN mainly involving megakaryocytic lineage
Sustained thrombocytosis >600x109/L
Incidence 1.5 per 100000
Mean age two peaks 55 years and minor peak 30 years
Females :males equal first peak but females predominate second peak

Question 24

Essential thrombocythaemia clinical presentation

Answer 24

Incidental finding in half the patients
Thrombosis: arterial or venous: CVA, gangrene, TIA, DVT or PE

Bleeding: mucous membrane and cutaneous
Minor: headaches, dizziness visual disturbances
Splenomegaly usually modest

Question 25

Treatment for essential thrombocythaemia

Answer 25

Aspirin: to prevent thrombosis Anagrelide: specific inhibition of platelet formation, side effects include palpitations and flushing Hydroxycarbamide: antimetabolite. Suppression of other cells as well. Possible mildly leukaemogenic

Question 26

Prognosis of essential thrombocythaemia

Answer 26

Normal life span may not be changed in many patients. Leukaemic transformation in about 5% after >10 years Myelofibrosis also uncommon, unless there is fibrosis at the beginning

Question 27

Primary myelofibrosis

Answer 27

A clonal myeloproliferative disease with proliferation mainly of megakaryocytes and granulocytic cells, associated with reactive bone marrow fibrosis and extramedullary haematopoieisis Primary presentation: Incidence 0.5-1.5 /100000 Males=females 7th decade. Less common in younger patients Secondary to other haematological disease: progression from PV or ET

Question 28

Clinical presentation of primary myelofibrosis

Answer 28

Incidental finding in 30% Cytopenias: anaemia or thrombocytopenia Thrombocytosis Splenomegaly: may be massive: Budd-Chiari syndrome Hepatomegaly Hypermetabolic state: Weight loss, Fatigue and dyspnoea, Night sweats, Hyperuricaemia

Question 29

Early stages of myelofibrosis

Answer 29

Prefibrotic stage Blood changes mild but may also be confused with ET Hypercellular marrow

Question 30

Later stages of myelofibrosis

Answer 30

Fibrotic stage Splenomegaly and blood changes Dry tap, with prominent collagen fibrosis and later osteosclerosis.

Question 31

Blood film findings on primary myelofibrosis

Answer 31

Leucoerythroblastic picture Tear drop poikilocytes Giant platelets Circulating megakaryocytes Liver and spleen: extramedullary haemopoiesis in spleen and liver

Question 32

Bone marrow findings in primary myelofibrosis

Answer 32

Dry tap Trephine: increased reticulin or collagen fibrosis, prominent megakaryocyte hyperplasia and clustering with abnormalities New bone formation

Question 33

Prognosis for primary myelofibrosis

Answer 33

Median 3-5 years, but very variable

Question 34

Bad prognostic signs in primary myelofibrosis

Answer 34

Severe anaemia <10g/dL Thrombocytopenia <100x109/l Massive splenomegaly Prognostic scoring system (DIPPS): Score 0 -- median survival 15years Score 4-6– median survival 1.3 years

Question 35

Treatment of primary myelofibrosis

Answer 35

Often symptomatic Anaemia: transfusions: may become increasingly difficult because of splenomegaly Platelet transfusions often ineffective Splenectomy for symptomatic relief: often hazardous and followed by worsening of condition Cytoreductive therapy: hydroxycarbamide for thrombocytosis, may lead to worsening of anaemia Ruxolotinib JAK2 inhibitor (high prognostic score) Bone marrow transplant in young patients may be curative (experimental)

Question 36

Clinical features of CML

Answer 36

``` M:F 1.4:1 40-60 years (but can occur at any age) Weight loss, lethargy, night sweats Lethargy/ hypermetabolism/ thrombotic event : monocular blindness CVA Splenomegaly +/- hepatomegaly: enlarged due to infiltration of cords and red pulp by granulocytes - this same process occurs in the liver hepatic sinusoids. Features of anaemia Bruising/bleeding Gout ```

Question 37

FBC findings in CML

Answer 37

Hb and platelets well preserved or raised | Massive leucocytosis 50-200

Question 38

Blood film in CML

Answer 38

Mature myeloid cells Neutrophils and some myelocytes (not blasts if chronic phase) Basophilia No excess (<5%) myeloblasts

Question 39

CML

Answer 39

CML is one of the Myeloprolifive disorders that arises from an abnormal pluripotent BM stem cell

Question 40

Natural history of CML

Answer 40

Not the clinical course, as this is altered by treatment Chronic phase: -approximately 80% of patients with CML are diagnosed in the chronic-phase -can last from a few months to about 4-5 years -nearly 80% of patients with CML will progress from the chronic-phase to the accelerated-phase -5% or fewer of the cells in the blood and bone marrow are blast cells Accelerated phase: 10-19% of the cells in the blood and bone marrow are blast cells Median 6-12 months Blast crisis: ≥20% of the cells in the blood and bone marrow are blast cells Median survival 3-6 months

Question 41

What is the Philadelphia chromosome

Answer 41

Produced by t(9;22) producing a fusion oncoprotein with tyrosine kinase activity (BCR-ABL fusion gene) Translocation of part of the long arm (q) of c/some 22 to c/some 9 And reciprocal translocation of part of c/some 9, which includes the ABL oncogene to a specific breakpoint cluster region (BCR) of c/some 22 A fusion gene results on the derived c/some 22 This leads to the synthesis of an abnormal protein with TK activity greater than the normal ABL protein

Question 42

Detection of Philadelphia chromosome

Answer 42

FISH

Question 43

How can you monitor disease and response to therapy in CML

Answer 43

FBC and leucocyte count: restored to normal FBC (complete haematological response WBC<10) Cytogenetics and detection of Ph chromosome: reduction in percentage of Ph metaphases (partial 1-35% Ph +ve, complete 0% Ph +ve) RT-PCR of BCR-ABL: log reduction in BCR-ABL ratio (BCR-ABL transcripts reduce 100% >10% >1% >0.1%. Major molecular response <0.1%)

Question 44

Types of BCL-ABL

Answer 44

Various BCR ABL mRNA transcripts are formed according to the position of the breakpoint in BCR In CML the breakpoint on the BCR gene is nearly always in the major breakpoint cluster region (M-BCR) Breaks in the major BCR occur either between exons b2 and b3, generating a fusion transcript with a b2a2 junction, or between exons b3 and b4 generating a fusion transcript with a b3a2 junction Breaks in the minor BCR give rise to BCR ABL mRNA molecules with an e1a2 junction

Question 45

Treatment of CML

Answer 45

Pathogenesis is an activated Tyrosine Kinase cABL Oral active ABL kinase Inhibitor (TKIs): 1st Generation Imatinib (Glivec) 2nd generation Dasatanib, and Nilotinib

Question 46

Prognosis for CML

Answer 46

Commence on oral TKI 1st generation Monitor response FBC, Cytogenetics, RQ-PCR: CCyR at 12mo 97% FFP at 6 years (Fail to achieve CCyr 80%) Average 95% 5 year survival Annual mortality 2% If loss or failure to respond switch to second generation TKI and consider allogeneic stem cell transplant