In order to investigate the functional consequence of TRIM59 inactivation or overexpression in vivo, we orthotopically injected MCF7 cells and MDA-MB-231 cells stably expressing shTRIM59 or TRIM59-internal ribosome entry site-green fluorescent protein (TRIM59-IRES-GFP), respectively, with Matrigel (1:1) into the NOD scid gamma (NSG) mouse mammary fat-pad and monitored tumor growth up to 10 weeks. The gene discussed is TRIM59; the disease is neoplasm.