Alterations in expression of phosphatase and tensin homologous (PTEN) gene analyzed in the bronchial lavage samples of non-small cell lung cancer patients

Aim: In this study, we aimed to analyze the expression of the Phosphatase and Tensin Homologous gene (PTEN) by interphase-fluorescence in situ-hybridization (iFISH), and localization and immunoreactivity of PTEN by immunocytochemistry method in bronchoalveolar lavage (BAL) fluid of patients with non-small cell lung cancer (NSCLC).Material and Methods: BAL samples collected from 30 patients diagnosed with NSCLC and from 10 control subjects without any malignancy were included. iFISH was performed with a 10q23.3 PTEN DNA dual color FISH probe, analyzing multiple cells. Immunocytochemistry was based on the Streptavidin-Biotin-Peroxidase method and PTEN levels were semi-quantitatively scored.Results: The percentage of cells with 2G/2R was 86.8% which was significantly lower than that of the control group (p<0.0001). Loss of the PTEN gene was 6.43% among all patients. The percentage of cells with monoallelic deletion (p=0.0246) and atypical signal (p=0.0001) and the percentage of monosomic cells (p=0.0001) were significantly higher in patients compared to controls. PTEN immunopositivity was significantly increased in patients compared to controls (p<0.0001).Discussion: Increased abnormal signals and mutational cells in BAL samples of NSCLC patients suggest that the investigation of the PTEN gene in BAL by using iFISH may guide clinicians in differential diagnosis and therapeutic management of NSCLC. Being faster, easier and cost-effective in routine testing, the immunocytochemistry method can also be combined as a diagnostic tool with molecular methods.