Comparison study of the performance of the QIAGEN EGFR RGQ and EGFR pyro assays for mutation analysis in non-small cell lung cancer.

OBJECTIVES: To compare 2 laboratory assays commonly used in the evaluation of epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC). METHODS: Fifty-three formalin-fixed, paraffin-embedded NSCLC specimens were selected. Extracted DNA was analyzed using the EGFR RGQ Amplification Refractory Mutation System Scorpions probe-based real-time polymerase chain reaction (PCR) assay and the EGFR Pyro pyrosequencing assay. RESULTS: Fourteen EGFR mutations were identified in 13 specimens using at least 1 of the assays, with a mutation concordance rate of 92.9%. Using dideoxy sequencing as the gold standard, clinical sensitivity was 73.7% and 68.4% by the RGQ and Pyro assays, respectively, but 100% by both for common drug sensitivity mutations. Performance observations included the following: the RGQ system requires higher DNA input, the RGQ system is a single-step procedure, the EGFR Pyro assay is a 2-step procedure, only the RGQ system can identify exon 20 insertions, the RGQ system is more sensitive, and the Pyro system can specify exact mutations for all interrogated sites. CONCLUSIONS: Both the RGQ real-time PCR and Pyro assays adequately detect common EGFR mutations; however, the RGQ system is more clinically and analytically sensitive. Performance characteristics should be considered when evaluating these EGFR mutation assays for clinical adoption.