Figure 2.

Pre-treatment pHPV levels according to disease stage. Boxplots with median pHPV value in % of total level of circulating free DNA. Lines are ranges. Outliers (n = 8) were removed. (A) The pHPV level increases non-significantly with increasing tumor (T) stage. (B) Comparison of pHPV between lymph node negative (N negative) and lymph node positive (N positive) tumors. (C) A higher level of pHPV is detected for T2-T3 and/or N positive tumors (high-risk) compared to T1-T2, N negative tumors (low risk). Statistical significance (*) were calculated using Wilcoxon–Mann–Whitney test.