Background: Somatic mutations of the epidermal growth factor receptor (EGFR) gene have been associated with tumor response to tyrosine kinase inhibitors (TKIs) and favorable outcome in patients with non-small-cell lung cancer (NSCLC). The activating mutations that confer sensitivity to EGFR TKIs are present in the TK domain of the EGFR gene. This study aims to report on the prevalence of EGFR mutations in NSCLC and non-squamous lung cancer patients at diagnosis, using genomic deoxyribonucleic acid (DNA) obtained from paraffin-embedded tissue samples.
Materials and methods: We collected formalin.fixed, paraffin.embedded. (FFPE) tissue samples from 166. cases of lungadenocarcinomas referring to Jordan University Hospital and King Hussein Cancer Center between 2007 and first half of 2013. None of the patients met the definition of never smoker defined as those who smoked less than 100 cigarettes in their lifetime. We evaluated EGFR mutations by nested polymerase chain reaction. (PCR) followed by direct sequencing of the EGFR kinase domain from exon 18 to 21.
Results: Six different point mutations were detected in 24 patients (14.46%) of the study population. The resultant mutations were as follows: Ten patients have deletion in exon 19, sevenpatients have L858R, two patients have L861P, and one of each of the following: A735T, D770_N771 insY, L858P, L861Q, and G917C.
Conclusion: The present study revealed that the EGFR mutations rate in Jordanian patients with adenocarcinoma of the lung was higher than in African-American, and some white Caucasian patients, and was lower than in patients in East Asia, and other countries of South Asia.