To characterize our isolated LC-CD133 + , FACS analysis was used to detect the expression profile of cells surface markers. As shown in Figure 2A , the majority of isolated LC-CD133 + were stained with higher expression levels of CD133, CD117 (c-Kit), and ABCG2 compared with LC-CD133 2 . This result demonstrated that isolated LC-CD133 + were almost ABCG2-positive cells (Fig. 2B) . To further evaluate the enhancement of tumorigenicity of LC-CD133 + , we examined in vitro Matrigel-combined Transwell invasion and soft agar colony formation assays. Compared with LC-CD133 2 , LC-CD133 + derived from NSCLC Patients No.1 (PLC) and No. 2 (LLC) showed higher invasion activity through Matrigel Transwell invasion assay (p,0.001; Fig. 2C ). Similarly, the foci formation ability of LC-CD133 + from PLC (No.1) and LLC (No.2) was enhanced when compared with the LC-CD133 2 of those two patients (p,0.001; Fig. 2D ).