Case #2 highlights a notable limitation of commercially available PCR-based assays, which may miss as many as 50% of EGFR exon 20 insertions, a critical mutation found in up to 12% of NSCLC tumors with EGFR mutations that accounts for roughly 4% of all NSCLC cases (17, 18). Here, EGFR is linked to non-small cell lung carcinoma.