Maps of the studied sequences. (A) Schematic representations of the genomic regions are shown. The gene names and the chromosomal locations are given. Vertical bars indicate the positions of CpG dinucleotides. Exons are shown above as black rectangles; arrows indicate the known or presumed transcriptional start sites. Red bars below specify the regions analysed by bisulphite pyrosequencing; blues bars indicate the area studied with bisulphite Sanger sequencing; the magenta bar shows the region studied by direct bisulphite sequencing of the SFRP1 PCR-product. (B) Methylation patterns of the Wnt/β-catenin pathway inhibitor genes. Each square represents a CpG site. The degree of methylation was measured by bisulphite pyrosequencing in the EHEB and MEC-1 cell lines, in 12 patient samples (CLL1 to CLL12) and CD19+ B cells from healthy donors. At the bottom, an intensity scale is shown. Results for SFRP1 were obtained by direct Sanger sequencing of the respective amplicon.