Detection of epidermal growth factor receptor gene mutations in non-small cell lung cancers by real-time polymerase chain reaction using scorpion amplification refractory mutation system / 中华病理学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate mutations of EGFR gene in non-small cell lung cancers (NSCLC) using scorpions amplification refractory mutation system (Scorpions ARMS) is in comparing the detection sensitivity with that by PCR-direct sequencing method, and in addition to study the correlation between the mutations and the clinicopathological characteristics of the patients.</p><p><b>METHODS</b>Tumor cells were collected by microdissection from paraffin embedded tumor specimens and adjacent normal lung tissues of 82 NSCLC patients. The genomic DNA was extracted. Mutations of EGFR gene (exons 18, 19, 20 and 21) were detected by PCR-direct sequencing and Scorpions ARMS methods respectively.</p><p><b>RESULTS</b>Somatic mutations were identified involving the tyrosine kinase domain of the EGFR gene in 42 of 82 cases with a mutation detection rate of 51.2% by Scorpions ARMS assay. In-frame deletions of exon 19 occurred in 20 patients and point mutation occurred at codon 858, 861 (exon 21) in 18 and 1 patients respectively. Two patients had insertions mutations and 1 patient had point mutation occurring at codon 768 (exon 20). Among the 58 informative cases analyzed by PCR-direct sequencing, 25 mutations (detection rate of 30.5%) were identified. In-frame deletions of exon 19 occurred in 13 patients and point mutation occurred at codon 858, 861 (exon 21) in 10 and 1 patients respectively. In addition, 1 patient had point mutation at codon 768 (exon 20). Overall, Scorpions ARMS assay was more sensitive in detecting mutations of EGFR than PCR-direct sequencing.</p><p><b>CONCLUSIONS</b>A higher incidence of somatic mutations of EGFR gene was detected in NSCLC of Chinese patients. Mutations were more common in female, non-smoking patients with adenocarcinoma and bronchioloalveolar carcinoma histology. Scorpions ARMS method is quicker, more sensitive and accurate in detecting the EGFR gene mutations and should provide important therapeutic and prognostic information to the clinicians.</p>