BMI1 and neoplasm: These data show that BMI1-silenced tumor cells significantly secrete low levels of BMI1 protein and BMI1-overexpressed CaP cells secreted significantly high levels of BMI1 protein in the culture media, the data suggest that intracellular BMI1 is directly correlated with the secretory BMI1 protein levels (Fig. 3A–F; p<0.05).