Epithelial-to mesenchymal transition (EMT) plays a crucial role in tumor progression and onset of metastases. Particularly, the role of E-cadherin and N-cadherin has to be still well investigated in lung cancer patients (LCP). The aim of our research is to study EMT in biologic fluids of lung cancer patients and to correlate them with tumor behaviour (histologic findings and prognosis).
One hundred LCP and a control group with benign lung diseases undergoing lung resection will be enrolled in the study. Only patients receiving R0 resection will be part of the study. We will collect preoperatively the bronchoalveolar lavage (BAL), pleural lavage (PL) and peripheral blood (PB); BAL and PL will be processed for cytology and biomolecular assays, PB for biomolecular assays. PL is performed with instillation of 300 ml of sterile saline solution in the chest cavity and collection of at least 70 ml of fluid. Standard histology of the surgical specimen will be performed. All patients will undergo standard clinical follow-up. PB withdrawal will be performed for biomolecular analyses preoperatively, at 1 week, 3, 6, 12 months and 2 years. Biomolecular assays will include real-time quantitative PCR for mRNA of E-cadherin and N-cadherin and will be calculated relative changes in gene expression. The results will be compared with the qualitative and quantitative neoplastic circulating-free DNA in the peripheral blood and with data from non ¿ neoplastic patients.
We hypothesis that in the biologic fluids of LCP the gene expression of E-cadherin and N-cadherin will be inversely represented (high level of E-cadherin in less aggressive tumor and high level of N-cadherin in more aggressive cancer with) and that this may predict prognosis; furthermore we believe that exists a correlation between levels of E-cadherin and N-cadherin with the neoplastic circulating-free DNA present in the PB of LCP and that it may contribute to early detection of recurrences.
Lung cancer is the leading cause of cancer death in men and women worldwide, accounting for more than 1.5 million deaths per year. This burden weights on society economics and on national health systems and leads to the need of establishing new methods for early diagnosis and staging to improve outcome. Validation of biomarkers that can easily be measured in biologic fluids improves the assessment of variables that can be used to design the most appropriate treatment plan for each patient. The studies carried out until now highlight the potential of non-invasive tools in lung cancer diagnosis; indeed, diagnosis at an early stage has a significant effect on the long-term survival. This is crucial since, despite improvements in early diagnosis of lung cancer through screening programs, still in too many cases this disease is diagnosed at an advanced stage. Therefore, the identification of novel diagnostic biomarkers, such as circulating tumor cells, cell-free DNA, mRNA and microRNA is critical and extremely important.
It was established by several studies that epithelial ¿ to - mesenchymal transition (ETM) is linked to unfavourable prognostic markers and poor prognosis in several malignant tumors, including lung cancer. During ETM transition, cancer cells lose their mechanisms of adhesion and acquire the anchorage-independent growth ones, which lead to migration, invasion, increased metastatic potential, immunosuppression and drug resistance. The critical step during epithelial-to-mesenchymal transition is the cadherin switch, which is the decrease in the expression of E-cadherin, a transmembrane receptor, essential in the formation of intercellular junctions, associated to a simultaneous increase of the expression of the transmembrane cell-cell adhesion protein N-cadherin. Even in extremely small quantities, mRNA of E-cadherin and N-cadherin can be detected by sensitive techniques such as real-time quantitative polymerase chain reaction (RT-PCR) from biological fluids.
For these reasons, we will investigate mRNA extracted from pleural effusion and bronchoalveolar lavage (BAL) and, by RT-PCR to evaluate the correlation between E-cadherin and N-cadherin expression levels and clinicopathological variables and their clinical significance in patients with the diagnosis of lung cancer. Moreover, we will correlate these data with the levels of circulating free DNA extracted from plasma of lung cancer patients because the presence of high plasmatic levels of free-circulating DNA in lung cancer patients has been described in several studies. So, the integration of ETM gene expression and circulating free DNA as biomarkers in biological fluids could provide an approach for the early detection and prognosis of lung cancer.
This study may have the potential to develop a method for the early detection and prognosis assessment of lung cancer that may be highly specific, sensitive, reproducible and moreover that may be safe and acceptable to the patients due to their non-invasive nature. No such study has been designed so far.