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P1.03 - Chemotherapy/Targeted Therapy (ID 689)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Chemotherapy/Targeted Therapy
- Presentations: 1
- Coordinates: 10/16/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
P1.03-001 - Verification and Implementation of the VENTANA Anti-ALK D5F3 Antibody in Detecting ALK Rearrangement in NSCLC (ID 7422)
09:30 - 16:00 | Author(s): C. Higgins
NSCLC patients with ALK rearrangement (2-7%) are usually young, non-smokers and benefit from targeted first and second lines tyrosine kinase inhibitor e.g. Crizotinib. The gold standard test for ALK in patients with proven metastatic or locally advanced NSCLC is fluorescence in situ hybridisation (FISH), however, immunohistochemistry (IHC) for ALK protein overexpression such as the VENTANA anti-ALK (D5F3) antibody is a useful screening test for ALK status in NSCLC patients as it has a high negative predictive value. Positive or equivocal cases can be confirmed by FISH.
Accreditation standards require laboratories to verify equipment and reagent performance before adopting into routine practice. We tested cytology and histology NSCLC samples of primary lung origin using anti-ALK (D5F3) antibody for ALK status using the VENTANA IHC platform and compared the findings against the gold standard FISH methodology. We tested 50 consecutive NSCLC samples of which 3 were excluded as FISH failed.
Of the remaining 47 samples, one was ALK positive by IHC and FISH and the remaining 46 were negative by both methods. As there were no false positive or negative cases by IHC, sensitivity, specificity, PPV and NPV were all 100%. We then proceeded to adopt reflex ALK testing by IHC as verification was achieved and confirmed equivocal and positive cases by FISH. In total we have tested 213 cases with ALK IHC equivocal in only 4 instances and one false positive (PPV = 85.7%). All 5 cases were negative by FISH (table below). Figure 1
ALK by IHC can be implemented to identify patients’ ALK status with confirmatory reflex testing by FISH for equivocal or positive cases in a cost effective and efficient process so that ALK positive patients can receive targeted TKI. Established cutting protocol to maximise tissue use is essential for tissue preservation and turn around times.