Oncology Cytogenetics

The department provides a routine service for chromosome analysis in leukaemia and lymphoma, providing information for diagnosis, prognosis and disease management.

Sample Type

Bone marrow is the preferred sample in analysis of haematological disorders.

For analysis of lymphoma, a fresh lymph node biopsy is required.

Prompt dispatch to the laboratory is essential. Any delay may compromise results. Samples should be taken into heparinised transport medium, (supplied by the department on request).

Additional FISH studies can be done on the above samples, but also on paraffin embedded tissue, blood or bone marrow smears, etc.

Reporting Times

 

Condition Reporting Time (days) Priority
Urgent FISH 3 (working days) Urgent
ALL Preliminary result = ASAPFull analysis = 14 Urgent
AML 14 Urgent
CML Preliminary result = 7Full analysis = 14 Urgent
Relapse samples 14 Urgent
MPD 21 Routine
MDS 21 Routine
Myeloma 21 Routine
CLL 21 Routine
Other haematological 21 Routine
Lymphoma 21 Routine
All follow up samples 21 Routine
Guidelines state that 95% of the samples should be reported within the guideline time (calendar days unless otherwise stated).

 

Analysis

Chromosome analysis in cancer allows the detection of genetic changes in tumour cells, which have been acquired during the disease process. Some changes are characteristic of a particular malignancy e.g. the t(15;17)(q24;q21.2) seen in acute promyelocytic leukaemia (APML). Other abnormalities are seen in a number of diseases e.g. t(9;22)(q34;q11.2) or Philadelphia rearrangement, which is characteristic of chronic myeloid leukaemia (CML), but is also seen in acute lymphocytic leukaemia (ALL) and acute myeloid leukaemia (AML). The abnormalities often aid in prognosis and are considered in many of the malignancy trial protocols.

The Philadelphia rearrangement shown below is typical in chronic myeloid leukaemia. At the molecular level this rearrangement results in the creation of a novel fusion gene, with increased tyrosine kinase activity and malignant potential. Understanding of this rearrangement allows its detection by sensitive molecular methods, such as DNA analysis and FISH (molecular cytogenetics), important in monitoring residual disease and relapse. The understanding of the molecular nature of the rearrangement has allowed the development of a specific treatment using tyrosine kinase inhibitors, such as Imatinib, in these patients.

 APML-15_17

Philadelphia-9_22