Background: Biopsies obtained from lung cancers contain a mixture of cancerous and healthy tissues. The mutant-enriched polymerase chain reaction (ME-PCR) identifies low-level somatic DNA mutations within an excess wild-type sample.
Aims: This study aimed at comparing nonenriched PCR (NE-PCR) versus ME-PCR for the detection of two epidermal growth factor receptor (EGFR) gene mutations among nonsmall cell lung cancer patients.
Methods: Fifty lung tissue biopsies were screened for inframe TTAA deletions in exon-19 and the L858R point mutation in exon-21, using ME-PCR and NE-PCR, followed by capillary electrophoresis.
Results: Only exon-19 deletions were detected in 22% and 18% of cases using ME-PCR and NE-PCR, respectively. Diagnostic performance of the NE-PCR versus the ME-PCR serving as a "gold standard" revealed a sensitivity of 82%, and a specificity of 100%, with positive and negative predictive values of 100% and 95%, respectively, and an overall accuracy of 96%. Despite a strong agreement shown between the two assays (K=0.875), the NE-PCR showed an 18% false-negative rate in bronchoscopically obtained biopsies compared to ME-PCR.
Conclusion: The false negativity encountered with NE-PCR in bronchoscopically obtained samples makes ME-PCR the technique of choice in such situations.