Evaluation of EGFR gene expression and four diagnostic mutations in EGFR in lung cancer patients

Lung cancer is the second most common cancer in men and women and is one of the most preventable cancers. a small number of known mutations of the EGFR gene for diagnostic purposes are being studied in laboratories and research centers in our country (Iran), the present study aimed to investigate 4 important EGFR gene mutations in lung cancer patients in the Iranian population in order to provide a method for early diagnosis and improvement of prognosis in lung cancer. Lung paraffin tissue samples were prepared from the pathology department of Imam Hossein Hospital in Tehran. DNA and RNA extraction was performed and mutations studied included 4 diagnostic point mutations in the EGFR gene named G719A (2156G>C) in exon 18, R776C (2326C>T) in exon 20, L861Q (c.2582T> A) in exon 21 and L858R (c.2573T> G) in exon 21. The expression level of the EGFR gene was evaluated using Real-Time PCR. The results of examining the 4 mutations by qRT PCR method in patients showed that G719A, R776C, L861Q, and L858R were positive in 11,7%, 4.2%, 4.2%, and 6% of patients respectively and these frequencies in the case group were significantly higher than the control group.  Results of EGFR expression showed overexpression in the case group in comparison with the control group (fold change 8, p-value=0.001). The results of the present study showed that common mutations of EGFR gene including G719A, L861Q, R776C, and L858R mutations in the Iranian population show a significant frequency and this study succeeded in first designing the correct primers and setting up the PCR program in the form of a multiplex reaction to evaluate 4 mutations simultaneously.