NPC1 and cancer: To validate the results, we used the CRISPR/sgRNA system to deplete NPC1 in different human cancer cell lines and observed a decreased cell growth in MM ARP-1 and RPMI-8226 (another MM cell line), HepG2, SKOV3, colon cancer HCT116, and breast cancer MDA-MB-231 cells (Figures S2D, S2E).