Table 1. Real-time PCR of methylated and unmethylated HPV-18 L1 DNA with unspecific primers but specific probes.

The cycle-threshold (c_T) show that methylated DNA could only be detected with methylation specific probes and unmethylated DNA with probes specific for unmethylated DNA, although the PCR primers and amplification conditions were the same in all four reactions. 0 = no signal. All c_T values of this table as well as of table 2 and 3 are arithmetic means of duplicate experiments.

	Methylated plasmid	unmethylated plasmid
Probe for methylated DNA	32.3	0
probe for unmethylated DNA	0	31.9