Facs analysis on tumor cells pooled from tumors derived from either treated or control animals, revealed decreased number of CD133+ and ABCG2+ BTICs in tumor from 4-HPR treated animals (Fig 7E and 7F) confirming in vivo the ability of fenretinide to target the MB stem component shown in vitro (Fig 6). Here, ABCG2 is linked to neoplasm.