Abstract

Cancer Stem Cells (CSCs) that are responsible for the onset and continuation of the tumour, they have an effective DNA repairing mechanisms, highly Multidrug Resistance/MDR transporters and also, they are silent cells protected in a hypoxic niche and are resistant to radiotherapy and chemotherapy. This small cell group, which is also highly resistant to apoptosis, is known to form other cancer cells once it has formed in the tissue. It is known that, after surgical removal of tumour tissue and/or after chemotherapy and radiotherapy applications, fewer cancer stem cells that remain in the region can re-establish tumour tissue and are responsible for recurrence of the disease. Cancer stem cells are also held responsible for metastasis seen after many years in many cancer cases that are thought to be treated. It is seen that CSCs show Epithelial Mesenchymal Transition (EMT) during metastasis and invasion. Recent studies also show that EMT stimulating factors simultaneously elicit CSC-like features in cancer cells. In summary, EMT is necessary for the acquisition and continuity of CSC characteristics and is therefore directly related to the recurrence and metastatic processes of NSCLC. However, the mechanisms that regulate these processes are still unknown.