Lung cancer is the leading cause of cancer death worldwide. Non-Small-Cell Lung Cancer (NSCLC) represents a high percentage of all lung tumours. Nowadays there are drugs and therapies aimed at the cancer subtype or driver mutations. These directed therapies were possible thanks to a deeper genome knowledge and advances on gene mutation screening. In lung cancer, survival is still low due to most patients not being able to benefice from directed therapy and chemotherapy treatments failing frequently. One of the factors that may be contributing to this outcome is the cancer stem cell population (CSC) in the tumour. CSC are believed to be responsible for the aggressiveness and cancer progression. This thesis focused on the identification and characterization of CSC subpopulations in NSCLC. We have used the ATCC cell lines A549, H1395, H1650, H1993 and PC9; and we have also stablished our own lines, derived from NSCLC resected tumour. We have developed a methodology to grow tumorospheres, a culture enriched in CSC. Thanks to injections in immunocompromised mice, we were able to confirm the tumor-initiating ability, an important CSC trait. We were able to identify potential CSC markers comparing the multiparametric flow cytometry of monolayer and tumorspheres cultures. Using Multiparametric flow cytometry we studied CMT markers from resected tumours. Despite the present high variability, some of the CSC potential markers were correlated with clinicopathological variables, but these results need to be validated in larger cohorts. Our results identify potential CSC markers in NSCLC and their signalling pathways. In particular EpCAM shows the activation of a signal transduction pathway in tumorospheres of our established lines. Thanks to gene analysis techniques, we identified 6 genes, CD44, NOTCH3, ITGA6, NANOG, P21 y SNAI1, overexpressed on our stablished lines’ tumorospheres, which we hope will be useful for the identification of CSC population in adenocarcinoma.
