To investigate whether MSC-TRAIL is capable of inducing intrinsic apoptosis in CD133+ CSCs, both the MSCs (MSC-EV and MSC-TRAIL) and CD133+ NSCLC (H460, H2170 and A549)-derived CSCs, as well as the CD133− and unsorted cells, were co-cultured (NSCLC-cell-to-MSC ratio, 1:1) for 72 h and assayed for mitochondrial membrane potential (ΔΨ) (Figure 7). The gene discussed is PROM1; the disease is non-small cell lung carcinoma.