Finally, cell lines that exhibited a spindle-like morphology in culture, were derived from either pleural effusions or primary tumor tissues and were largely comprised of EpCAM-/CD24-/CD49f+ Mesenchymal cells (> 90%) (Figure 4a, Additional files 4 and 6); thus, referred to as Mesenchymal lines. Here, ITGA6 is linked to Pleural effusion.