ROS1 Analyte Control^DR

ROS1 is a receptor tyrosine kinase (RTK) encoded by the ROS1 gene. Genetic rearrangements can occur with many different partner genes many of these translocations are associated with a variety of tumors, in particular lung.

Our ROS1 control DR consists of three cell lines: a negative cell line; absence of any ROS1 fusion protein. A very low expressing cell line with the FIG-ROS1 deletion-translocation and a high expressing cell line with a SLC34A2-ROS1 translocation and resulting fusion protein.

Along with our ALK-Lung (EML4-ALK) Analyte Control and PD-L1 Analyte Control^DR, the ROS1 Analyte Control further adds to to our non-small cell lung carcinoma range of biomarker controls.

ROS1 is frequently assessed by immunohistochemistry (IHC) or Next Generation Sequencing (NGS). Initially fluorescence in situ hybridization was the primary test for ROS1 and while still used it has been superseded by IHC and NGS. The latter allows the assessment of a panel of genes and their mutations. However, IHC allows the direct assessment of the fusion protein, the very target the drugs act on.

The low expressing cell line is of glioblastoma origin. The FIG-ROS1 fusion, also known as GOPC-ROS1. This is an interstitial deletion where the 5′ end is lost rather than translocated as seen with SCL34A2-ROS1 where the 5′ end resides elsewhere on another chromosome.

It is important to note that the FIG-ROS1 is not identified by all FISH assays. Agilent ROS1 FISH gives a false negative demonstrating overlapping signals. FIG-ROS1 is an interstitial deletion that gives rise to a fusion protein hence it is detected by IHC optimised appropriately.