Moreover, IHC of sections from xenograft tumors showed increased levels of the proliferation marker Ki67 in MB231-GPS2KO tumors as compared to their WT counterparts (Figure 2E), thus indicating that the increased tumor burden in a breast cancer model of GPS2 depletion is due, at least partially, to increased proliferation of GPS2 null cells. The gene discussed is MKI67; the disease is neoplasm.