Comparison of cobas EGFR Mutation Test v2 and PANAMutyper-R-EGFR for Detection and Semi-Quantification of Epidermal Growth Factor Receptor Mutations in Plasma and Pleural Effusion Supernatant

ABSTRACT

BACKGROUND: Plasma epidermal growth factor receptor (EGFR) mutation tests are less invasive than tissue EGFR mutation tests. We determined which of two kits is more efficient cobas EGFR Mutation test v2 (cobasv2; Roche Molecular Systems, Pleasanton, CA, USA) or PANAMutyper-R-EGFR (Mutyper; Panagene, Daejeon, Korea). We also evaluated whether pleural effusion supernatant (PE-SUP) samples are assayable, similar to plasma samples, using these two kits. METHODS: We analyzed 156 plasma and PE-SUP samples (31 paired samples) from 116 individuals. We compared the kits in terms of accuracy, assessed genotype concordance (weighted κ with 95% confidence intervals), and calculated Spearman's rho between semi-quantitatively measured EGFR-mutant levels (SQIs) measured by each kit. We also compared sensitivity using 47 EGFR-mutant harboring samples divided into more-dilute and less-dilute samples (dilution ratio ≥ or <11,000). RESULTS: cobasv2 tended to have higher accuracy than Mutyper (73% vs 69%, P=0.53), and PE-SUP samples had significantly higher accuracy than plasma samples (97% vs 55–71%) for both kits. Genotype concordance was 98% (κ=0.92, 0.88–0.96). SQIs showed strong positive correlations (P<0.0001). In less-dilute samples, accuracy and sensitivity did not differ significantly between kits. In more-dilute samples, cobasv2 tended to have higher sensitivity than Mutyper (43% vs 20%, P=0.07). CONCLUSIONS: The kits have similar performance in terms of EGFR mutation detection and semi-quantification in plasma and PE-SUP samples. cobasv2 tends to outperform Mutyper in detecting less-abundant EGFR-mutants. PE-SUP samples are assayable using either kit.