Investigating Common Mutations in Exon 20 and 21 of EGFR Gene in Lung Cancer Tumor Tissue of NSCLC Type

Abstract

Background: A mutation in the EGFR gene can be a marker for non-small cell lung cancer (NSCLC). The frequency of this mutation is very different in various countries and ethnic groups. Objectives: This study investigated the frequency of mutations in exons 20 and 21 of the EGFR gene in patients with NSCLC in Iran. Methods: Twenty paraffin blocks with an average age of 3 years were prepared from the Tehran Cancer Institute. The samples belonged to 5 women and 15 men aged 61 - 74 years and were confirmed by a pathologist in terms of positivity and type of tumor. After deparaffinization, DNA extraction was performed using a QIAGEN kit. The appropriate probes and primers were designed, and finally, the samples were examined by the real-time TaqMan method, and the data were analyzed. Results: The findings showed that 15% and 10% of patients had mutations in exon 20 and 21 of the EGFR gene, respectively. The T790M mutation of exon 20 was observed in three patients (tumors of adenocarcinoma type and large cell cancer), and L858R and L861Q mutations of exon 21 of the EGFR gene were observed. Conclusions: The frequency of mutation in exon 20 and 21 of the EGFR gene in NSCLC patients among Iranians is close to Middle Eastern and European patients, but it is very different from the frequency of this mutation among East Asian and North Asian patients.