The results obtained with osteosarcoma cells were confirmed for HeLa cells in which we found a higher expression of the CXCR4 stem cell marker, a higher SP fraction in cells overexpressing RAB39A, and a reduced CXCR4 expression and SP fraction in cells with knockdown of RAB39A (Supplementary Figure 2A to 2F). The gene discussed is CXCR4; the disease is osteosarcoma.