Immunostaining of the multifoci showed markedly higher COX4-1 and BMI1 levels, along with substantially more Ki-67 staining that associated with multiple tumor loci in U251-TgCOX4-1 xenografts compared with parental controls (Figure 3), suggesting that COX4-1 expression promotes in vivo tumor cell proliferation. The gene discussed is BMI1; the disease is neoplasm.