Digital droplet PCR-based quantification of ccfHPV-DNA as liquid biopsy in HPV-driven cervical and vulvar cancer

PurposeMore than 99% of cervical cancers and up to 40% of vulvar cancers are human papillomavirus (HPV) related. HPV 16 and 18 are the most relevant subtypes. Novel technologies allow the detection of minimal amounts of circulating cell-free HPV DNA (ccfHPV-DNA). The aim of this study was to evaluate ccfHPV-DNA assessed by droplet digital PCR (ddPCR) as a biomarker for molecular therapy monitoring in early, advanced, relapsed and metastatic HPV-driven cervical and vulvar cancer.MethodsInclusion criteria of the study were histologically proven HPV 16/18-driven cervical and vulvar cancer with first diagnosed disease, newly diagnosed recurrence, or progression of disease. Blood samples were taken pre- and post-therapeutically. Circulating cell-free HPV DNA was quantified using ddPCR and the results were correlated with clinical data.ResultsThe mean copy number of ccfHPV-DNA was 838.6 (& PLUSMN; 3089.1) in pretreatment and 2.3 (& PLUSMN; 6.4) in post-treatment samples (p < 0.05). The copy number of ccfHPV-DNA increased with higher FIGO stages (p < 0.05), which are commonly used for clinical staging/assessment. Furthermore, we compared the distribution of copy numbers between T-stage 1 versus T-stage 2/3. We could show higher copy number level of ccfHPV-DNA in T-stage 2/3 (p < 0.05).ConclusionsTherapy monitoring with determination of ccfHPV-DNA by ddPCR with a small amount of plasma reflects response to therapy and appears feasible for patients in advanced cancer stages of cervical and vulvar cancer. This promising tool should be examined as marker of therapy monitoring in particular in novel HPV-directed therapies.

Automated summary

The aim of this study was to evaluate the use of circulating cell-free HPV DNA (ccfHPV-DNA) assessed by droplet digital PCR (ddPCR) as a biomarker for molecular therapy monitoring in early, advanced, relapsed, and metastatic HPV-driven cervical and vulvar cancer. The results showed that the detection of ccfHPV-DNA can reflect treatment response and is particularly feasible in advanced stages of cervical and vulvar cancer.