Test name:

Order name:
ROS1 by FISH request

Specimen requirements:
Formalin fixed paraffin-embedded tissue (FFPE)

Minimum volume:
FFPE – 2 unstained 4µm thick sections on positively charged slides plus 1 stained H&E slide of the same block

Storage and Stability information:
Room temperature

Test performed:
Twice per week

Fluorescence in situ hybridization

Reference range:
See lab report

Clinical significance:
Gene fusions involving ROS1 are present in 1-2% of non-small cell lung carcinomas, primarily adenocarcinomas. Several partner genes (FIG, SLC34A2, CD74) have been identified.  Resulting activation of ROS1 kinase activity appears to be a principal growth driver in these tumors. This kinase is sensitive to crizotinib, and patients with ROS1-fusion positive tumors have shown responses to this inhibitor. This test utilizes a break-apart FISH probe to the ROS1 locus to screen for these gene fusions by FISH.

CPT codes:
88368 x 2