Anaplastic lymphoma kinase 5A4 immunohistochemistry as a diagnostic assay in lung cancer: A Canadian reference testing center's results in population‐based reflex testing

摘要: Background The presence of anaplastic lymphoma kinase (ALK) rearrangement predicts response to ALK tyrosine inhibitor (TKI) therapy. Fluorescence in situ hybridization (FISH) was the initial reference standard detect rearrangement, but immunohistochemistry (IHC) using D5F3 has gained acceptance as an alternative diagnostic method. IHC assays other antibodies have also been used screening methods, data supporting their utility tests not widely reported. Methods Data from reflexive clinical test 5A4 clone concurrent with epidermal growth factor receptor (EGFR) mutation testing were analyzed. results reported negative (-), equivocal, or positive (+), equivocal staining validated by FISH break-apart probe testing. Treatment outcomes reviewed for IHC+ patients. Results Between 2012 and 2015, 146 (2.5%) cases IHC+, 188 (3.2%) 5624 (94.4%) IHC-. Of cases, 131/143(91.6%) FISH+. Excluding 6 which inconclusive performed, predictive value 95.6%, 100%. Most specimens (n = 5352 [89.6%]) successfully tested EGFR. Clinical responses TKIs noted 49 patients, a median progression-free survival 9.9 months. Conclusions can serve robust ALK-rearranged lung cancer is associated treatment survival. Optimized tissue allocation resulted high success rates combined reflex EGFR