Use of test
Purpose:
Chromosomal abnormalities resulting in deletion at 7q or monosomy 7 can occur in both acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS). Genes in the deleted region include EPO, PLANH1 and MET. Deletions at 7q are also common in therapy-related AML/MDS. These abnormalities have prognostic implications.
Utility:
Monosomy 7q is an indicator of poor prognosis, often occurring in association with other cytogenetic abnormalities.
Ethical considerations:
This is an assay for non-heritable mutations. It does not raise issues of ethics or consent that are different from most other investigations ordered in the routine care of a patient.
Methodology:
Fluorescent in situ hybridisation (FISH) analysis, using probes within the region of 7q commonly deleted in AML/MDS. This interphase FISH test has a cut off at 5%. A low level of positive cells may be due to overlap of the two signals. Studies of normal controls indicate that this level is less than 5%. Small abnormal populations may therefore not be detectable.
Requesting the test
Ordering:
This test is usually requested by a haematologist or oncologist. In the investigation of myelodysplasia, it is usually requested as part of the Myelodysplastic syndrome FISH panel.
Sample required:
0.5 mL bone marrow in transport media (or 10 mL blood in lithium heparin if blasts >10%).
To help ensure the quality of the test, a genetic test should be done with a dedicated sample whenever possible i.e. a sample collected specifically for that test rather than a sample that is used for multiple tests.
We recommend that the patient or another adult check the labelling of request forms and sample tubes.
Turnaround time:
2 business days.
Price:
Up to $255.
If more information is required, the requesting clinician can call our laboratory on (07) 3377 8573.
Rebate:
This test is not rebated by Medicare. The laboratory assumes that the patient or client has provided informed financial consent for the test.