The department provides a routine service for chromosome analysis in leukaemia and lymphoma, providing information for diagnosis, prognosis and disease management.
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.
|Condition||Reporting Time (days)||Priority|
|Urgent FISH||3 (working days)||Urgent|
|ALL||Preliminary result = ASAPFull analysis = 14||Urgent|
|CML||Preliminary result = 7Full analysis = 14||Urgent|
|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).|
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.