The MDM2 oncogene is located on the long arm of Chromosome 12. Overexpression of this gene occurs in many types of cancer.
The overall frequency of MDM2 amplification in human tumours is 7%. The highest frequency is observed in soft tissue tumours (20%), osteosarcomas (16%) and oesophageal carcinomas (13%). This test has diagnostic implications.
In cases of unclear diagnosis, the presence of MDM2 gene amplification can be of assistance in distinguishing between (i) lipomas and atypical lipomatous tumour/well-differentiated liposarcomas, (ii) malignant undifferentiated tumours and dedifferentiated liposarcomas, and (iii) a variety of benign tumours and liposarcomas.
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 to the MDM2 gene. This test is performed on thin sections of tissue, so some cells in the section may be sliced by the process, and only contain some of the regions of interest. Sections may contain bony, fatty or necrotic material, which may interfere with processing and/or analysis. Dense tissue also makes identification of individual cells difficult. The accuracy of the results is dependent on the correct identification of tumour on the sections provided, and the assumption that positive results will be identified by a large proportion of cells within the tumour having a rearrangement.
Formalin-fixed, paraffin embedded tissue (FFPE) - 15 sections of 4 uM thickness, dried overnight at 37°C onto charged/coated slides.
Please label each slide with patient and block identifiers plus number them sequentially 1-15. Stain slides 1 and 15 with H&E and leave slides 2-14 unstained. The request should be accompanied by the somatic mutation request form (above)and a copy of the original histopathology report.
Up to 4 weeks.
If more information is required, the requesting clinician can call our laboratory on (07) 3377 8573.
An MBS rebate is available, if criteria are met (item number 73374). If requested with other FISH probes, an MBS rebate is available if criteria are met (item numbers 73375, 73376).