Non-small cell lung cancer (NSCLC) is the most common form of lung cancer, and the ALK inhibitors have potential in targeted treatment of the disease. However, they are only effective in patients who have rearrangements in the anaplastic lymphoma receptor tyrosine kinase (ALK) gene. A team of German researchers have created a PCR (polymerase chain reaction) based assay that could make detecting the genetic changes simple and straight forward, making personalised medicine possible for certain lung cancer patients.
The standard approved test for ALK gene rearrangements involves dual-colour fluorescence in situ hybridization (FISH). This process is complex, costly and time consuming, and interpreting the results isn’t always easy, so it’s not completely appropriate for use in day to day practice. The German team has developed a test based on quantitative reverse transcriptase PCR (PCR) to amplify RNA extracted from routine formalin-fixed, paraffin-embedded tumour samples.
In a study of NSCLC 182 tumour samples, comparing the PCR technique with FISH, the German team’s test accurately typed 97% of 19 tumours with ALK rearrangements and 158 with no rearrangements. The results have been published in the Journal of Thoracic Oncology.
“The qRT-PCR technique reliably detects ALK-rearranged tumors independently of the fusion partner and also identifies tumors with full-length transcript expression of the gene that is not detectable by FISH but may be relevant for ALK inhibitor therapy as well,” says lead author Claudia Kalla of the Robert-Bosch-Krankenhaus and the Dr Margarete Fischer-Bosch Institute of Clinical Pharmacology in Germany. “The technique seems to be a sensitive, easy-to-perform, and high-throughput method suitable for the routine diagnosis of ALK activation not only in lung cancer, but also in other tumour entities where rearrangements with alternative fusion partners or transcriptional upregulation are prevalent.”