Effect of the DNA demethylating agent Aza on CD44 expression. (A) Expression of CD44 was re-inducible by treatment of cells with 5 μM Aza (3 days) in CD44 hypermethylated cell lines, but not in CD44 unmethylated cell lines as assessed by qRT-PCR. Expression levels of the corresponding DMSO-controls were set to 1. (B) Aza (5 μM) treatment for 4 days induced CD44 protein expression in CD44 hypermethylated cell lines as analyzed by flow cytometry. CD44 stained cells (filled histogram) and isotope control labeled cells (open histogram) are shown. M: methylated; U: unmethylated; increase of CD44 positive cells: - = no change, + = > 10%, ++ = > 25%.