Methylation status of 3.3-kb repeats by sodium bisulfite sequencing in cervical tissues, tumors, and cell lines. Sq-1, Sq-2, and Sq-3 mark three regions of 3.3-kb monomer selected for sequencing. Each row of circles represents a cloned DNA molecule; closed circle, methylated CpG; open circle, unmethylated CpG; dot, CpG site lost from the consensus sequence due to mutations; cross, CpG site status was not determined. The percentage of methylated CpGs among all CpGs analyzed is given below each sample. Nc, normal cervix from non-cervical-cancer patients; T, tumor; N, tumor – tumor-adjacent normal tissue. Numbers of patients are indicated as in Figure 3C. Only P values below 0.05 are given (χ-square test).