Figure 3.

Bisulphite pyrosequencing analysis of the PTEN CpG island. Shown are representative pyrograms of region 2 (panel A) and region 6 (panel B) of the PTEN CpG island from the colorectal cancer cell line RKO. A, Region 2 was completely unmethylated in all samples tested. B, Region 6 showed a mean of 12% methylation across the 6 CpG sites tested in the colorectal cancer cell line RKO. Indicated by the black arrow is the presence of an A nucleotide variant specific to the PTENP1 pseudogene suggesting non-specific amplification of PTENP1. Blue boxes indicate the percent methylation at each CpG site. Grey shading indicates the CpG sites tested. Yellow shading indicates bisulphite conversion control dispensations, which indicated complete conversion in all samples tested.