An inexpensive and rapid testing method can effectively identify a sub-group of never-smoking lung cancer patients whose tumors express a molecule associated with increased risk of disease progression or recurrence, US researchers have found.
Dr Ping Yang from the Mayo Clinic, Rochester, USA, and colleagues, reported the findings at the European Multidisciplinary Conference in Thoracic Oncology (EMCTO), 24-26 February 2011, Lugano, Switzerland.
Approximately 8% - 12% of patients with lung adenocarcinoma who have never smoked cigarettes carry tumors that express a protein product called anaplastic lymphoma kinase (ALK), Dr Yang said. "This subset of patients are at more than double the risk of experiencing disease progression or recurrence within 5 years of initial diagnosis compared to never-smokers whose lung adenocarcinoma tumors are ALK-negative."
The ability to test for ALK status in these patients may help doctors select the most appropriate therapies for maximum clinical benefit, Dr Yang explained. Her group's study aimed to see whether immunohistochemistry screening, followed by a confirmatory test using fluorescence in situ hybridization (FISH), is a practical way to do this.
Immunohistochemistry tests use antibodies to identify specific proteins in tissue sections; FISH uses fluorescent probes to bind to specific DNA sequences in the chromosomes of individual cells.
In a study of 303 samples, the research team found that immunohistochemistry results correlated well with the results of FISH. Tissue samples with the highest immunohistochemistry scores (IHC 3+) were all FISH positive, while those with no immunohistochemistry staining (IHC 0) were FISH negative.
Based on these findings, only samples that were scored with the intermediate IHC scores of 1+ and 2+ would need confirmatory testing with FISH, Dr Yang explained. "In this particular cohort, IHC score 2+ and 1+ cases represented approximately
|Contact: Vanessa Pavinato|
European Society for Medical Oncology