O10. Allele-specific real-time PCR detection of EGFR exon 19 and 21 mutations in various clinical non-small cell lung cancer specimens

Background: The aim of our study was to evaluate the effectiveness of epidermal growth factor receptor (EGFR) gene mutation detection in diverse materials from 707 non-small cell lung cancer (NSCLC) patients using the two ultra-sensitive allele-specific real-time polymerase chain reaction (PCR) assays in the routine diagnostic procedure.

Methods: A total of 629 samples were analyzed by PNA-LNA PCR clamp, 164 samples by CE-IVD certified allele-specific PCR assay and 86 samples by both methods. PNA-LNA PCR clamp products were analyzed by Sanger sequencing to confirm rare mutations. NSCLC specimens were characterized by tumor cells content and type of fixation (Table 1).

Table 1 NSCLC specimens characterized by tumor cells content and type of fixation
Full table

Results: A number of 62/707 (9%) specimens were positive for EGFR mutations: 32 detected in exon 19, including four rare deletions and p.R748K substitution (c.2243G >A); 28 p.L858R (c.2573T >G) mutations, one rare variant of p.L858R (c.2572_2573delinsAG) and one double mutation p.L858M + p.L861Q (c.2572C >A; c.2582T >A) detected in exon 21. There were 71% women in the EGFR+ group. 98% of EGFR+ were adenocarcinoma samples, thus mutation frequency among adenocarcinoma patients was 9.8% (61/617 patients). Ultrasensitive PNA-LNA PCR clamp assay and allele-specific PCR CE-IVD test presented high results conformity with 95.3% overall percent agreement (95% CI: 90.9-99.8) and Cohen’s Kappa score of 0.9 (95% CI: 0.88-0.92).

Conclusions: Both real-time PCR assays provided reliable and robust detection of most common EGFR activating mutations in various clinical NSCLC specimens.

Keywords: Non-small cell lung cancer (NSCLC); epidermal growth factor receptor (EGFR) mutations; molecular testing