Methylation analysis of the ER, RARβ, and p16 genes. A, G is undigested genomic DNA as positive control, H is HpaII, and M is MspI. The band in H of control lanes indicates lack of digestion with HpaII and, therefore, methylation of untreated MDA-231 cells. B and C show the analysis by methylation-specific PCR of RARβ and p16 genes in MCF-7 and T24 cells. W is wild type, M is methylated primers, and U is unmethylated primers. D and E show a time course experiment of RARβ and p16 gene demethylation over 5 days on the MCF-7 and T24 cells, respectively. (Reproduced with permission from the AACR. Ref. 83. Clin Cancer Res 2003, 9:1596–1603).