Week 9 - Leukemia

Question 1

What is leukemia?

Answer 1

Leukemia is a group of blood cancers arising from the uncontrolled proliferation of dysfunctional white blood cells (leukocytes) in the bone marrow. The replacement of normal marrow cells with immature blasts leads to marrow failure, anaemia, thrombocytopenia, and neutropenia.

Question 2

How does leukemia affect the body?

Answer 2

It replaces normal bone marrow with abnormal blast cells, reducing the production of healthy red cells, white cells, and platelets. This results in anaemia (fatigue), thrombocytopenia (bleeding), and neutropenia (infections).

Question 3

What are the main risk factors for developing leukemia?

Answer 3

Exposure to ionizing radiation or chemotherapy

Genetic disorders (e.g., Down syndrome)

Chromosomal abnormalities or translocations

Viral infections (e.g., HTLV-1)

Advanced age (acute types in children, chronic in older adults)

Question 4

How is leukemia classified?

Answer 4

Leukemia is classified as:
- Acute or chronic (based on disease progression)
- Myelocytic or lymphocytic (based on cell lineage)

Question 5

What are the four major subtypes of leukemia?

Answer 5

Acute Myeloid Leukemia (AML)

Chronic Myeloid Leukemia (CML)

Acute Lymphoblastic Leukemia (ALL)

Chronic Lymphocytic Leukemia (CLL)

Question 6

What is the key difference between acute and chronic leukemia?

Answer 6

Acute leukemia: >20% blasts, rapid onset, severe symptoms

Chronic leukemia: <20% blasts, slow onset, may be asymptomatic

Question 7

Which leukemias commonly affect different age groups?

Answer 7

ALL & AML: Occur in both children and adults (bimodal distribution)

CLL & CML: Occur mostly in older adults

Question 8

What are the clinical features of acute leukemia?

Answer 8

Fever, lethargy, bleeding

Hepatosplenomegaly and lymphadenopathy

Bone pain (especially spine and long bones)

Anaemia symptoms (fatigue, shortness of breath)

Thrombocytopenia symptoms (bruising, heavy menstrual bleeding)

Question 9

What are the clinical features of chronic leukemia?

Answer 9

Often asymptomatic at diagnosis

May have hepatosplenomegaly and lymphadenopathy

Bleeding and bruising are less common

Question 10

What defines Acute Myeloid Leukemia (AML)?

Answer 10

20% myeloid blasts in bone marrow

Most common acute leukemia in adults

Highly aggressive with variable prognosis

60% achieve remission, but only 15–30% remain disease-free after 5 years

Question 11

What is the pathophysiology of AML?

Answer 11

Caused by chromosomal translocations and mutations leading to abnormal myeloblast production.

A key abnormality: t(15;17) translocation → fusion of RARA and PML genes → acute promyelocytic leukemia, often associated with DIC.

Question 12

What defines Chronic Myeloid Leukemia (CML)?

Answer 12

Caused by chromosomal abnormalities in hematopoietic stem cells

Leads to overproduction of dysfunctional granulocytes (neutrophils, basophils, eosinophils)

Question 13

What genetic abnormality is characteristic of CML?

Answer 13

Philadelphia chromosome: translocation between chromosome 9 (ABL1) and chromosome 22 (BCR) forming the BCR-ABL1 fusion gene, causing overactive tyrosine kinase and uncontrolled cell proliferation.

Question 14

What defines Acute Lymphoblastic Leukemia (ALL)?

Answer 14

Blastic transformation of B or T cells

Most common leukemia in children (80%)

Caused by chromosomal translocations or abnormal chromosome numbers in lymphoid precursor cells

Question 15

What defines Chronic Lymphocytic Leukemia (CLL)?

Answer 15

Proliferation of monoclonal B lymphocytes

Occurs mainly in people aged 60–70

Leads to gradual immune dysfunction

Question 16

What is the pathophysiology of CLL?

Answer 16

Mutations occur during early B-cell development → enhanced survival and proliferation

Immune stimulation and genomic lesions drive clonal B-cell expansion

Interaction with the microenvironment sustains disease progression

Question 17

How is leukemia diagnosed?

Answer 17

Complete Blood Count (CBC)

Peripheral blood and bone marrow smear

Flow cytometry and cytogenetic testing to determine leukemia subtype

Question 18

What are the main treatment options for leukemia?

Answer 18

Chemotherapy – standard treatment for most types

Targeted therapy – e.g., Tyrosine kinase inhibitors (CML), BCL2 inhibitors (CLL)

Radiation therapy – for local control or specific cases

Stem cell transplantation – for eligible patients

Supportive care – transfusions, antibiotics, and growth factors

Question 19

What is the prognosis of leukemia?

Answer 19

Prognosis varies by subtype:
- AML: 60% remission with chemotherapy; 15–30% long-term disease-free
- ALL: Better prognosis in children than adults
- CML & CLL: Often managed chronically with targeted therapy

Question 20

What are the hallmark laboratory findings in leukemia?

Answer 20

Elevated or decreased white blood cell count

Presence of immature blasts in peripheral smear

Anaemia and thrombocytopenia

Abnormal cytogenetic findings (e.g., Philadelphia chromosome)