Chronic Myeloid Leukaemia (CML)

Exam Cram

• Chronic Myeloid Leukaemia is a type of blood cancer, whereby the haematopoietic stem cells undergoes genetic damage

• Presentation: asymptomatic, nausea, B-symptoms: night sweats, fevers, weight loss; raised WCC

• Diagnosis: bone marrow biopsy shows creation of philadelpia chromsone- ABL1 gene from chromosone 9, joins onto the BCR gene in chromosone 22

• Management: tyrosine kinase inhibitors (imatinib) block the effect of the ABL-BCR genetic abnormality and are highly effective

Outline

Background

• 95% of CML is caused by a single genetic mutation: ABL from chromosome 9, translocating onto BCR on chromosome 22 to create the Philadelphia chromosome

• CML cells are typically monoclonal replications of this genetic abnormality

• The ABL-BCR mutation causes tyrosine kinase overproduction, hence the tyrosine kinase inhibitors are highly effective with only a 5% risk of disease progression over 5 years; a medical success story

Assessment

Presentation

• Asymptomatic

• Fatigue, bruising, infections

• Abdominal bloating, nausea, anorexia

• Night sweats, fevers, weight loss

Examination

• Splenomegaly (can be massive)

• Sometimes hepatomegaly

Investigations

• Deranged FBC: high white cells of myeloid lineage- neutrophils, esinophils, basophils, monocytes, platelets, RBC

• Blood film: myeloid cells staining for ABL-BCR

• Bone marrow biopsy: trephine/ aspirate- ABL-BCR

Diagnosis

Diagnostic criteria: bone marrow biopsy- cytogenetics confirming Philadelphia chromosome abnormality

Management

First line

1. Tyrosine kinase inhibitors: Imatinib

Resources

References

1. CML — HaemBase : excellent haematology website. 

Links

• Physiology: Haematopoetic stem cells: Haematological & Immune System 

• Pathophysiology: Cancer & Mimics 

• Specialties: Haematology, Oncology 

Written in 2026