PROM1 and cancer: CD133 has been identified as one of the most abundant surface antigens that are highly expressed on several types of cancer CSCs including liver, brain, ovarian, lung, colorectal, and gastric (Yi et al., 2008; Baba et al., 2009; Hibi et al., 2010; Alamgeer et al., 2013; Yamashita and Wang, 2013; Zhang et al., 2014).