Understanding about the genetic changes behind cancer can help doctors create the best treatment patterns for patients. PCR (polymerase chain reaction) has been used to learn more about ROS1 fusion genes in lung cancer in East Asian patients, and look at its impact on clinical outcome and patient prognosis.
Patients carrying ROS1 fusion genes can have cancer that is sensitive to crizotinib, a drug approved for the treatment of non-small cell lung cancer (NSCLC) in patients with ALK gene fusions.
The researchers, from the National Taiwan University Hospital, used multiplex reverse transcription PCR (RT-PCR) to detect the ROS1 fusion gene in samples of tissue or fluid around the lungs (malignant pleural effusions) from patients with NSCLC, and used immunohistochemistry to confirm the expression of ROS1.
After identifying patients with the ROS1 fusion gene, they then compared the demographic data and clinical outcomes of patients with patients without the gene, including those with the EGFR mutation, EML4-ALK fusion, and KRAS mutation, and patients who were negative for all four genes. The results were published in the Journal of Thoracic Oncology, the official journal of the International Association for the Study of Lung Cancer.
Of the 492 lung cancer patients studied, 2.4% had the ROS1 fusion gene, and were significantly younger than those patients without the gene.
“The present study demonstrates that RT-PCR and IHC can successfully identity ROS1 gene fusion expression in both surgical and malignant pleural effusion specimens of lung adenocarcinoma without EGFR/ALK/KRAS mutations and the prevalence of ROS1 is similar to that found in other ethnic groups, which may help facilitate a diagnostic algorithm to identify patients who may benefit from a specific targeted-therapy” says Pan-Chyr Yang, MD, PhD, senior author.
There was no significant survival difference between the groups, but those patients with the ROS1 fusion appeared to have worse outcomes than EGFR-mutant patients in late stage disease. Further studies are needed, according to the researchers.