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CDKN2A FISH

Test category:

Oncology - Leukaemia

Use of test

Purpose:

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.

Utility:

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.

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 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

Ordering:

This test is usually requested by a haematologist or oncologist.

Sample required:

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.

Turnaround time:

5 business days.

Price:

The price varies according to the specific clinical conditions for a particular patient. Please contact Sonic Genetics on 1800 010 447 for more information.

Rebate:

This test is not rebated by Medicare. The laboratory assumes that the patient or client has provided informed financial consent for the test.