NOTE: Our laboratory offers multiple testing options for non-small cell lung cancer. Please see our Lung Cancer overview page.
OVERVIEW
ROS1 rearrangements have been reported in approximately 0.5-2% of non-small cell lung carcinomas (NSCLC) and are almost exclusively in those that do not habour an EGFR or KRAS mutation or ALK1 fusion.
ROS1 rearrangements can occur with a number of different partner genes, however all rearrangements involve the 3’ region of the ROS1 kinase domain with the 5’ region of the partner gene. The resulting fusion generates a constitutively active tyrosine kinase. Constitutively active ROS1 fusions are oncogenic and NSCLC carrying these rearrangements are sensitive to ROS1 tyrosine kinase inhibitor therapies.
INDICATION
Stage IIIB/IV non-small cell, non-neuroendocrine lung adenocarcinoma with ROS1 IHC of 1+,2+ and 3+.
TEST REQUIREMENTS
ROS1 FISH is typically performed as a confirmatory test for ROS1 IHC positivity (1+,2+ and-3+).
- Completed CGL Solid Tumour Testing requisition form
- ALK screening by IHC is automatically performed in combination with Focus Panel
- FFPE Tumour specimen (see Specimen Guidelines, Cytogenetics test type)
- A minimum of 10% tumour content and at least 100 nuclei is required
TURN-AROUND TIME
Results are reported within fourteen days from receipt of specimen and completed requisition form.
RESULTS REPORTING
- Specimens are reported as Positive for a rearrangement, Negative for a rearrangement, or Negative for a rearrangement – extra signals.
- Specimens with inadequate tumour tissue may be cancelled by the reviewing pathologist prior to receipt in CGL.
METHOD
FISH analysis is performed on the provided paraffin embedded tissue using the ROS1 (6q22) dual-colour, break-apart probe (BioCare Medical).
REFERENCES
- Melosky et al. Current Oncology (2018) PMID:29507487