Use of test
CDKN2A is a tumour suppressor gene. Inactivation of this gene by mutation, methylation or deletion plays a role in the progression of many cancers. Deletions are the most frequent mechanism in haematological malignancies, and these can be detected by FISH. The presence of a deletion can have diagnostic and prognostic implications.
CDKN2A deletions occur in up to 21% of B-cell precursor ALL and up to 50% of T-ALL patients. The prognostic effect is uncertain, with deletions possibly being a negative factor in childhood ALL.
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.
Fluorescent in situ hybridisation (FISH) analysis, using probes designed to detect CDKN2A gene deletion. 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%.
Requesting the test
This test is usually requested by a haematologist or oncologist.
0.5 mL bone marrow in transport media (or 5 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.
5 business days.
The price varies according to the specific clinical conditions for a particular patient. Please contact Sonic Genetics on 1800 010 447 for more information.
This test is not rebated by Medicare. The laboratory assumes that the patient or client has provided informed financial consent for the test.