UK NEQAS ICC & ISH: Non-Small Cell Lung Cancer EQA for ALK and PD-L1
Diagnostic pathology increasingly employs immunohistochemistry (IHC) for the classification and subsequent selection of patients for specific therapies. It is therefore important that External Quality Assessment (EQA) providers develop IHC modules that assess the quality of tests designed to guide molecular targeted therapy choice. Within the lung setting, ALK IHC and PD-L1 are now routinely being performed in many clinical laboratories.
Patients showing anaplastic lymphoma receptor tyrosine kinase gene (ALK) rearrangements in non-small-cell lung cancer (NSCLC) have shown to have a good clinical response to the drug Crizotinib. The fusion partners of ALK, EML4-ALK rearrangement was initially used as the front line test by fluorescence in situ hybridisation (FISH). However, more recently IHC has been accepted as a screening method for ALK rearrangements in NSCLC. With many laboratories now using IHC as the front line test for ALK in NSCLC, the UK NEQAS ICC & ISH scheme has been providing an external quality assessment for ALK in NSCLC. Results from the assessments carried out over 2 years show that although improvements have been made, there is still concern that some diagnostic laboratories are using inadequate staining methods, which has a direct impact on final interpretation. It is also significant to highlight to laboratories the importance of ideal in-house control material to correctly gauge the sensitivity of the assay.
More recently, PD-L1 IHC testing is now being used as a predictive test for several different cancers. Irrespective of the therapy choice, each of the different therapies will have a corresponding complementary biomarker or companion diagnostic (CDx) test in the form of an IHC assay. Setting up an EQA for PD-L1 IHC testing is set to be more challenging, especially with the advent of several PD-L1 therapies with their respective biomarkers, including the various antibody clones, such as 22C3, 28-8, SP142 and SP263, limitations of automated staining platforms, scoring algorithms, and cut-offs. The UK NEQAS ICC & ISH scheme recently carried out an educational pre-pilot PD-L1 assessment for NSCLC. Results from the assessment show that a variety of assays are being used by laboratories, including several lab-devised methods. Data from the assessment will be presented.
Selected Relevant Reference
Ibrahim M, Parry S, Wilkinson D, Bilbe N, Allen D, Forrest S, Maxwell P, O’Grady A, Starczynski J, Tanier P, Gosney J, Kerr K, Miller K, Thunnissen E. ALK Immunohistochemistry in NSCLC: Discordant Staining Can Impact Patient Treatment Regimen. J Thorac Oncol. 2016 Dec;11 (12):2241-2247. doi: 10.1016/j.jtho.2016.07.012. Epub 2016 Jul 25.
Suzanne has been working with the UK Neqas External Quality Assessment Scheme for Immunocytochemistry and In-Situ Hybridisation (UK NEQAS ICC & ISH) since 2011. As principal Scientific Officer Suzanne is responsible for overseeing all of the operational aspects for this large international organisation, monitoring quality within the testing of clinical healthcare services.
Suzanne qualified as a biomedical scientist in 1996, and her previous work appointments have primarily been within the field of Cellular Pathology, in both the clinical diagnostic and research fields, with a particular interest in breast pathology and research; including working for a number of years at the Breakthrough Breast Cancer Research Unit at the Institute of Cancer Research.