UCLA

Quantification of epidermal growth factor receptor (EGFR) mutations is important for the prediction of tyrosine kinase inhibitor (TKI) efficacy in patients with non-small cell lung cancer (NSCLC). However, clinicians lack a sensitive and convenient method to quantify EGFR mutant abundance. The present study introduces a novel method, namely amplification refractory mutation system (ARMS)-Plus, for the quantitative analysis of EGFR exon 19 deletion (19Del), L858R and T790M mutations. Formalin-fixed paraffin-embedded tumor samples were collected from 77 patients with lung adenocarcinoma. DNA was extracted and analyzed for EGFR mutations using ARMS-Plus. The performance of ARMS-Plus was then compared with that of conventional ARMS-polymerase chain reaction (ARMS-PCR) and droplet digital PCR (ddPCR). The results demonstrated that the concordance rate of EGFR mutation testing between ARMS-Plus and ddPCR was 98.7% (76/77, Kappa=0.9739). 19Del and L858R mutations were detected in 23 and 12 patients, respectively. There was a significant difference between ARMS-Plus and ddPCR in the evaluation of 19Del mutant abundance (P=0.0002); however, not in that of L858R mutant abundance (P=0.7334). The ARMS-Plus results in L858R mutant abundance were concordant with that of ddPCR (R2=0.8081). These results indicated that the sensitivity and specificity of ARMS-Plus in identifying EGFR mutations were similar to that of ddPCR. For quantitative analysis, the results of ARMS-Plus in evaluating L858R mutant abundance revealed a positive correlation with the ddPCR results. Thus, ARMS-Plus provides an alternative method, which is reliable and cost-effective, to quantify EGFR mutations and thereby, aid treatment decisions in patients with lung adenocarcinoma.