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Updated: Dec 16, 2025
Author Spotlight: Optimizing Digital Droplet PCR Method for Accurate Adeno-Associated Viral Genome Quantification
Published on: October 11, 2024
Droplet digital PCR quantification suggests that higher viral load correlates with improved survival in HPV-positive
A Stevenson1, K Wakeham2, J Pan3
1Centre for Virus Research, Institute of Infection Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
Background:
Although HPV-positive oropharyngeal cancer (OPC) patients have improved prognosis compared to HPV negative patients; there remains an HPV-positive group who have poor outcomes. Biomarkers to stratify discrete patient outcomes are thus desirable. Our objective was to analyse viral load (VL) by droplet digital PCR (ddPCR), in HPV-positive patients with OPC on whom clinical outcome data were available.
Methods:
In a cohort of patients that had previously tested HPV positive via conventional PCR, VL was determined using ddPCR assays for HPV16 L1 and E6 genes. VL was classed as "medium/high" if more than 5.57 copies or 8.68 copies of the HPV 16 L1 or E6 gene were detected respectively. Effect of VL on overall survival and hazard of death & disease progression was performed with adjustments made for sex, age, deprivation, smoking, alcohol consumption and stage.
Results:
L1 VL ranged from 0.0014-304 gene copies per cell with a mean of 30.9; comparatively E6 VL ranged from 0.0012-356 copies per cell with a mean of 37.9. Univariate analysis showed those with a medium/high VL had a lower hazard of death; this was significant for L1 (p = 0.02) but not for E6 (p = 0.67). The ratio of E6 to L1 deviated from n = 1 in most samples but had no influence on clinical outcomes.
Conclusions:
HPV viral load may be informative for the further stratification of clinical outcomes in HPV positive OPC patients.
