Real-time PCR for human papillomavirus (HPV) DNA load and physical status assay. (a) Typical amplification plots obtained by real-time PCR for 7-point series concentration of HPV-16 E6/7 plasmid DNA. The x axis denotes the cycle number and y axis the fluorescence intensity over the background. (b) Comparison of standard curves for the crossing points plotted against the HPV-16 E2 and E6/7 concentrations. The x axis denotes the cycle number and y axis the series concentration of HPV-16 plasmid DNA. Data are mean ± SE (n = 3).