Determination of the Expression Levels of EGFR, FGFR2, PIK3CA, PTEN, SMAD4, STK11, and TP53 Genes in Exhaled Breath Condensate Samples in Cases of Non-Small Cell Lung Cancer

Project no. 23878 · Status: Kapanmış (Yayın bekleniyor) · 2023

Summary

Lung cancer (LC) is a global health issue causing high mortality rates and significantly contributing to the incidence of new cases worldwide. Non-small cell lung cancer (NSCLC) is the most common type, with adenocarcinoma being the most frequent subtype. The aim of this study is to determine the expression profiles of EGFR, FGFR2, PIK3CA, PTEN, SMAD4, STK11, and TP53 genes in cell-free RNA (cfRNA) from exhaled breath condensate (EBC) samples collected from patients diagnosed with advanced primary lung adenocarcinoma with good performance status and from age- and gender-matched healthy individuals. This study also aims to demonstrate the validity of EBC in the diagnosis and prognosis of LC.The study included 40 cases diagnosed with advanced (Stage IIIB and IV) primary lung adenocarcinoma with good performance status, treated at the Ege University Faculty of Medicine, Department of Pulmonary Diseases, alongside a control group of 20 healthy individuals without a cancer diagnosis, matched for age and gender. From each participant, 2 mL of exhaled breath condensate was collected, and from randomly selected 10 cases from each of the cancer and healthy groups, 4 mL of EDTA-treated peripheral blood was drawn, and plasma was separated. RNA isolation from the EBC and plasma samples was performed using the PureLink RNA Mini Kit according to the kit manual. Expression analyses of the seven genes were conducted using designed primers and the RT SYBR Green qPCR Master Mix kit with a LightCycler 480 II instrument. Gene expressions were normalized to the GAPDH reference gene and quantified using the 2-ΔΔCT method. Correlation between gene expression changes obtained from EBC and plasma samples was assessed using linear regression analysis. ROC analysis was conducted on the expression levels of the seven genes to determine the sensitivity and specificity of lung cancer detection. Additionally, the clinical outcomes of the NSCLC patients were evaluated using Kaplan-Meier survival analysis.When comparing the expression levels of the seven genes in EBC samples to healthy controls, significant increases by more than two-fold were observed in PTEN, TP53, SMAD4, and FGFR2 gene expressions in the patient group. Furthermore, a significant correlation between EBC and plasma EGFR gene expression (R²=0.7849, p=0.0006) underscores the importance of these genes in the diagnosis and prognosis of NSCLC. Individuals with high FGFR2 and PIK3CA expression levels exhibited shorter survival times, whereas those with low expression levels had significantly longer survival times. Notably, patients with low EGFR levels undergoing chemotherapy had significantly longer survival times compared to those with high EGFR expression levels.In conclusion, the detailed analysis of gene expression profiles in EBC samples is crucial for determining the diagnosis, prognosis, and treatment responses in NSCLC. Further detailed investigations in larger patient cohorts are necessary to enable these genes to be used as effective biomarkers in prognostic assessment and treatment selection in advanced-stage cancer patients.

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