Rearrangements and abnormal expression of the ROS1 gene (also known as ROS, MCF3 or c-ros-1) have been described in approximately 1-2% of non-small cell lung carcinomas and other types of tumors. The detection of the ROS1 rearrangement in lung tumors allows applying a treatment with specific inhibitors in patients, which has shown a greater survival as compared to conventional chemotherapy.
The ROS1 Break Apart FISH probe is designed to detect rearrangements in the ROS1 human gene located in the band of the chromosome 6q22.1. Aside from detecting breaks that can lead to translocation of parts of the gene, to its inversion or to its fusion with other genes, the probe can also be used to identify other aberrations of ROS1 such as deletions or amplifications.
The 5’ telomeric fragment of the ROS1 Break Apart FISH probe labeled with the fluorochrome CytoGreen covers the 5’ portion (beginning) of the ROS1 gene and some adjacent genomic sequences. The 3’ centromeric fragment of the ROS1 Break apart FISH probe labeled with CytoOrange covers the 3’ part (end) and the adjacent and inferior sequences of the gene.Both probes are flanking sequences in the ROS1 gene, in which variable cut-off points have been observed.