Lecture 5: CML & Hemophilia Flashcards
Leukemia
- cancer of hemopoietic tissue that usually produces and extraordinary high number of leukocytes and their precursors
Myeloid Leukemia
AML/CML
uncontrolled granulocyte production
Lymphoid Leukemia
ALL/CLL
uncontrolled lymphocyte production
Chronic Myelogenous Leukemia (3)
- Myeloproliferative d/o of granulocytic cells
- abnormal cell line is increased in number, but cells produces are functionally inert
- the greater the tumor burden of these abnormal cells, the less marrow space and resources exist for other cells such as healthy white blood cells, red blood cells, and platelets
- results in infections, anemia, and bleeding
OVERVIEW
- uncontrolled production of mature and maturing granulocytes
- predominately neutrophils, but also basophils and eosinophils
Neutrophils
Phagocytic: bateria and fungi
Eosinophil
Parasites, allergy, inflammation response
Basophil
release histamine
Epidemiology CML
4 rx factors
- 1.5 cases per 100,000 in the US
- 4000 cases annually - rx factors
a. prior high dose radiation exposure (WWII/Chernobyl/Fuskashima)
b. exposure to certain organic solvents (benzene)
c. age: median age at presentation is 55 years
d. Male >female
CML Clinical Presentation (5)
- 30% asymptomatic
-elevated WBC >25,000/L
discovered incidentally - fatigue, night sweats, weight loss, fever
- abdominal fullness, pain and/or early satiety due to splenomegaly
- easy bruising and purpura
- sternal tenderness-may be a sign go marrow over expansion
Genetics CML
final result
final product
- Fusion of 2 genes:
a. BCR (chromosome 22)
b. ABL 1 (chromosome 9)
=fusion BCR-ABL 1 gene - final result: abnormal chromosome 22 called philadelphia (Ph) chromosome
- Final product: BCR-ABL 1 fushion protein, dysregulated tyrosine kinase
Cml and Ph chromosome
- detected chromosome abnormalities via FISH
Pathophysiology CML and Ph chromosome (4)
- the BCR (breakpoint cluster region) gene is located on chromosome 22 and is constitutively active
- proto-oncogene ABL on chromosme 9 codes for tyrosine kinase involved in growth regulation and has a well-regulated expression pattern
- translocation t(9;22) results in a fushion gene with loss of expression and regulation, leasing to increased tyrosine kinase activity and increased cell proliferation
- a philadelphia chromosome occurs in more than 90% of CML (classic CML)
BCR-ABL fusion protein and its role in CML pathogenesis (3)
- promotes cellular proliferation via tyrosine kinase activity
- oligomerazation of bcr/abl is crucial for oncogenicity
- tumor proliferation
- speed up cell divion
- inhibit DNA repair
Diagnostic Studies CML (4)
- Demonstrating the presence of the t(9:22) or its gene product is aboluletly essential in diagnosing a patient with CML*
- Cytogenetic analysis (karyotype) of bone marrow is needed in all cases at diagnosis
- ID Philadelphia chromosome and other chromosomal abnormalities - FISH
- can ID bcr/abl rearrangement even if philadelphia chromosome cannot be identifies by cytogenetic analysis - Quantitative polymperase chain reaction (PCR)
- baseline measure of bcr/abl transcript levels prior to the start of therapy
Phases CML based on 2 factors
- number of immature cells in the blood and bone marrow biopsy
- severity of patient’s symptoms
Early Stage CML
<10% blast cells in blood and bone marrow samples
Accelerated stage CML
10-20% blasts, platelet counts decline
-usually within 6-8 months