The Effects of EGFR Exon 19 747–750 Deletion on the Risk of Developing Lung Cancer

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Objective: Although smoking is the most significant factor in the etiology of lung cancer, other environmental pollutants and genetic predisposition also play major roles in its development. Histopathologically, lung cancers are divided into two major types, as small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). The latter accounts for almost 85% of all lung cancers with a very aggressive course and being associated with a high rate of mortality. Among the genetic mutations with prognostic value in NSCLC, the epidermal growth factor receptor (EGFR) mutation is most frequently found in 50 to 80% of cases. The EGFR is a transmembrane glycoprotein with tyrosine kinase activity which is associated with both normal cell growth and malignant transformations. Material and Methods: In the present study, we aimed to evaluate the effects of exon 19 747–750 deletion in the EGFR gene on the risk of developing lung cancer and to examine its potential relationship with the different histopathological types of lung cancer. The study sample comprised a total of 178 patients diagnosed with lung cancer at Mersin University, Medical Faculty, Oncology Clinics, and 192 age- and sex-matched healthy individuals as the control group. Deoxyribonucleic acid (DNA) isolation was performed using the standard salt-water precipitation method, while the mutation screening and genotyping analyses were carried out with a polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses. Results: The frequency of mutant EGFR exon-19 deletion in the control group was 15.1%, increasing to 36.9% in the lung cancer group, and increasing the risk of developing lung cancer by 2.64 times (p: 0.014). This increase did not significantly differ between the histopathological types of lung cancer (p: 0.76). Conclusion: Considering the distribution of lung cancer patients in different age groups, it is obvious that advanced age is a risk factor for the development of EGFR mutation and lung cancers (p<0.001).