Methodology: FISH

Clinical Significance:
ROS-1 is a an orphan receptor tyrosine kinase that is phylogenetically related to the ALK tyrosine kinase gene. ROS-1 rearrangements have been found to occur in approximately 2% of lung adenocarcinomas and several gene fusion partners have been identified including CD74, LRIG3, SDC4, TPM3, and FIG. Tumors that harbor a ROS-1 gene rearrangement have been found to be responsive to treatment with the ALK inhibitor drug crizotinib (Xalkori). Recent studies have demonstrated that FISH can be used to identify ROS-1 rearrangements in lung adenocarcinoma. A positive result with this test would therefore indicate that the patient may respond to treatment with crizotinib*. *NOTE: Determining insurance eligibility is the responsibility of the patient and their physician.

Organ: Lung

Disease State: Mesothelioma vs. Adenocarcinoma

CPT Code(s): 88374 (reference only; CPTs may vary)

Turnaround Time: Within 4-6 business days of receipt

Schedule: Monday - Friday

Specimen Requirements:
• Formalin-fixed, paraffin-embedded tissue block or cell block - OR - • Minimum of 5 unstained slide cut at 4µm for each test requested