Figure 5.

The quantification PCR-based methylation analysis of gastric and colon cancer cell lines. (A) CpG sites and Hpa II/Msp I sites in the human MDR1 promoter region. Top: The CpG sites are represented by the short vertical bars. The positions of exons 1 and 2 are indicated as closed boxes. The position corresponding to these fragments are indicated. Middle: Hpa II/Msp I recognition sites are represented by short vertical bars. Bottom, PCR primers used in methylation analysis. (B) Representative methylation status of the MDR1 promoter region by quantification PCR-based methylation analysis in SNU-5 (gastric) and HT-29 (colon). 1: MN, Never-methylated Hpa II/Msp I site at the triosephosphate isomerase gene promoter region (negative control) (240 bp); 2: MC, the positive control primer pair (240 bp); 3: MS1, Hpa II/Msp I site 1 (121 bp); 4: MS2, Hpa II/Msp I site 2 (206 bp).