Because CD133 has been identified as a powerful cancer stem cell marker, we then examined and found CD133 expression that on these three primary cultured cell lines in 10% FBS/DMEM/F-12 medium represented 10.2%, 69.7% and 27.5% of the total population examined on No. 1049, No. 377 and No. 66, respectively, by flow cytometry analysis (Fig. 2). Here, PROM1 is linked to cancer.