Immunohistochemistry is routinely performed in pathology labs and is a relatively inexpensive and rapid test method. "Because it is already performed in most pathology labs, testing can be done on-site versus sending a sample to another diagnostic testing site. Thus, IHC may be a good initial screening tool for ALK status," Dr Yang explained.
Overall, the researchers found that 8.2-12.2% of this never-smoking group with lung adenocarcinoma had tumors that expressed ALK. The ALK positive tumors were significantly more aggressive as measured by tumor grade of differentiation and stage, and were diagnosed in younger patients, Dr Yang said. However, there are no guidelines or standard protocols for ALK testing by IHC at the present time; proper standardization and validation of IHC procedures for ALK testing are needed, including evaluating the effectiveness of different antibodies, Dr. Yang added.
Commenting on the research, which she was not involved in, Dr Fiona Blackhall, Consultant Medical Oncologist and Honorary Senior Lecturer at The Christie Hospital NHS Foundation Trust, and Manchester Cancer Research Centre, UK said: "Dr Yang and colleagues have conducted an important study showing that immunohistochemistry may be an efficient screen to identify cases for confirmatory FISH. Their work provides a basis from which to evolve a practical, clinical testing algorithm that incorporates IHC as a first step."
"Further work is now needed to validate these findings, optimize the methodology for IHC and the criteria for FISH," Dr Blackhall added. "Their finding that patients with ALK-positive tumors may have a worse outcome following surgery is provocative, highlighting the clinical and therapeutic importance of identifying and learning more about this molecular subtype
|Contact: Vanessa Pavinato|
European Society for Medical Oncology