IMAGE: This is Kurtis Davies, Ph.D. view more
Credit: University of Colorado Cancer Center
Drugs like crizotinib are used to treat patients with ROS1-positive lung cancer. But which patients are ROS1-positive? A University of Colorado Cancer Center study published in the Journal of Thoracic Oncology shows that common laboratory tests used to determine ROS1 status all have inherent limitations that can lead to false-negative results. Some samples that were determined to be ROS1-negative by one test were shown to be ROS1-positive by another, meaning that some patients who could benefit from ROS1-directed therapy may be slipping through the cracks.
A commonly used test, based on a technique known as fluorescence in situ hybridization (FISH), provided a false negative for 2 of 20 samples known to be ROS1-positive; a test that sequences and analyzes ROS1 DNA was negative in 4 of 18 positive samples; and a test that looks for ROS1 fusion RNA was negative in 3 of 19 positive samples.
“The main point is just to be aware of the deficiencies in these assays and not to always trust a negative result from a single test. If you’re suspicious that a patient could be ROS1-positive – maybe they’re a
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