OPA1 deletion resulted in reduced engraftment (3/8 engrafted MDA-MB-231 OPA1−/− vs. 8/8 MDA-MB-231 OPA1−/−:OPA1), but because 37.5% of the implants attached, we could compare tumor growth that was almost nil for the MDA-MB-231 OPA1−/− compared to the MDA-MB-231 OPA1−/−:OPA1 grafts (Fig. 4b,c). The gene discussed is OPA1; the disease is neoplasm.