FISH for Synovial Sarcoma Test Cost & Procedure

Introduction

There are four different subtypes of synovial sarcoma, the most prevalent of which are the biphasic and monophasic subtypes. While monophasic synovial sarcoma only contains a spindle cell component, biphasic synovial sarcoma exhibits both epithelial and spindle cell components in different amounts. Undifferentiated and monophasic epithelial subtypes have also been identified, however they are significantly less frequent.

Using tests

The SS18 gene on chromosome 18 fuses with one of three associated genes on the short arm of the X as a result of the t(X;18) translocation. The inquiry finds evidence of SS18 breaking. The results of this test will aid in diagnosis.

Utility: Almost 80% of synovial sarcoma tumours exhibit the rearrangement, which is unique to this kind of tumour.

This test is designed to detect non-heritable mutations. In contrast to the majority of other examinations requested as part of a patient's routine care, it does not raise any ethical or consent-related difficulties.

The SS18 gene is used in fluorescent in situ hybridization (FISH) study, which uses probes to find gene fusions. Due to the tiny tissue sections used for this test, certain cells within the section may be cut during the procedure and may only include certain regions of interest. Bony, fatty, or necrotic material may be present in sections, which could hinder processing or analysis. Individual cell identification is also challenging in dense tissue. The accuracy of the results depends on the tumours on the given sections being correctly recognised, and on the supposition that a significant percentage of the cells in the tumour having a rearrangement will indicate positive results.

Asking for the test

This test is typically ordered by an oncologist.

Download the request form for somatic mutations in solid tumours.

Formalin-fixed, paraffin-embedded tissue (FFPE) must be provided in the form of 15 sections, each of which must be dried overnight at 37°C onto charged/coated slides.

Particular guidelines:

Kindly identify each slide with the patient and block numbers and number them in order from 1 to 15. Slides 2 through 14 should be left undisturbed whereas slides 1 and 15 should be stained with H&E. The somatic mutation request form (above) and a duplicate of the original histopathology report must be submitted with the request.

Time frame: up to 4 weeks.

In conclusion, 5–10% of all soft tissue sarcomas are synovial sarcomas.

It mostly affects males between the ages of 15 and 40, is most common in teenagers and young adults, and is frequently observed in juxta-articular regions, especially around the knee. Yet synovial sarcoma can also develop in places that don't seem to be connected to synovial structures, like the head and neck region and the trunk.