Also known as: FOXO1 FISH, FKHR FISH, FOXO1-PAX3, FOXO1-PAX7
Oncology - Sarcoma
Use of Test
The FOXO1 (also known as FKHR) locus is rearranged in around 80% of cases of Alveolar Rhabdomyosarcoma (RMS). 60% have a PAX3-FOXO1 fusion, and 20% a PAX7-FOXO1 fusion.
Diagnosis of RMS is often problematic histologically, and positivity for a FOXO1 gene fusion is a useful diagnostic aid. The presence of a FOXO1 gene fusion also has prognostic implications.
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 detect gene fusions involving the FOXO1 gene, including fusions with the PAX3 and PAX7 genes. 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).