SOX2 and non-small cell lung carcinoma: Subpopulations of several NSCLC lines that express plectin and that can be isolated with our PCS2 ligand or an anti-plectin antibody, express elevated levels of stem cell markers such as ALDH1A3, SOX2 and CD44. It is important to point out that these biomarkers are not always correlating due to the fact that tumor biomarker expressions are highly heterogeneous, which leads to the existence of various subpopulations within each cancer type21,33.