HPV circulating tumoral DNA quantification by droplet-based digital PCR: A promising predictive and prognostic biomarker for HPV-associated oropharyngeal cancers.
We aimed to determine whether pretherapeutic assessment of HPV circulating tumoral DNA (HPV ctDNA) by droplet-based digital PCR (ddPCR) could constitute a predictive and prognostic biomarker for HPV-associated oropharyngeal squamous cell carcinoma (OPSCC). A mono-institutional prospective biomarker study on 66 patients with p16+/HPV16-positive oropharyngeal squamous cell carcinoma (OPSCC) was conducted in European Georges Pompidou Hospital, Paris, France. Blood samples were collected at the time of diagnosis before any treatment. Optimized digital PCR assays were used to quantify HPV16 ctDNA. Forty-seven (71%) patients showed a positive pretherapeutic HPV ctDNA at time of diagnosis. Interestingly, the quantity of HPV16 ctDNA at baseline, as assessed by ddPCR, was significantly correlated with the T/N/M status or OPSCC stages according to the 2018 new staging criteria for high-risk human papillomavirus (HR HPV) related OPSCC from American Joint Committee on Cancer (AJCC). Moreover, all recurrences and the majority (83%) of death reported events occurred in patients with positive HPV16 ctDNA at baseline. Finally, when posttreatment blood samples were available (n = 6), the kinetic of pretreatment/posttreatment HPV16 ctDNA was clearly associated with treatment success or failure. HPV ctDNA monitoring by ddPCR could constitute a useful and noninvasive dynamic biomarker to select HR HPV-related OPSCC patients eligible for potential treatment de-escalation and to monitor treatment response.
Veyer D
,Wack M
,Mandavit M
,Garrigou S
,Hans S
,Bonfils P
,Tartour E
,Bélec L
,Wang-Renault SF
,Laurent-Puig P
,Mirghani H
,Rance B
,Taly V
,Badoual C
,Péré H
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Development of a high-performance multi-probe droplet digital PCR assay for high-sensitivity detection of human papillomavirus circulating tumor DNA from plasma.
To develop a high-performance droplet digital PCR (ddPCR) assay capable of enhancing the detection of human papillomavirus (HPV) circulating tumor DNA (ctDNA) in plasma from patients with HPV-associated oropharyngeal squamous cell carcinoma (HPV+ OPSCC).
Plasma samples from subjects with HPV+ OPSCC were collected. We developed a high-performance ddPCR assay designed to simultaneously target nine regions of the HPV16 genome.
The new assay termed 'ctDNA HPV16 Assessment using Multiple Probes' (CHAMP- 16) yielded significantly higher HPV16 counts compared to our previously validated 'Single-Probe' (SP) assay and a commercially available NavDx® assay. Analytical validation demonstrated that the CHAMP-16 assay had a limit of detection (LoD) of 4.1 copies per reaction, corresponding to < 1 genome equivalent (GE) of HPV16. When tested on plasma ctDNA from 21 patients with early-stage HPV+ OPSCC and known HPV16 ctDNA using the SP assay, all patients were positive for HPV16 ctDNA in both assays and the CHAMP-16 assay displayed 6.6-fold higher HPV16 signal on average. Finally, in a longitudinal analysis of samples from a patient with recurrent disease, the CHAMP-16 assay detected HPV16 ctDNA signal ∼ 20 months prior to the conventional SP assay.
Increased HPV16 signal detection using the CHAMP-16 assay suggests the potential for detection of recurrences significantly earlier than with conventional ddPCR assays in patients with HPV16+ OPSCC. Critically, this multi-probe approach maintains the cost-benefit advantage of ddPCR over next generation sequencing (NGS) approaches, supporting the cost-effectiveness of this assay for both large population screening and routine post-treatment surveillance.
Bhambhani C
,Sandford E
,Haring CT
,Brummel C
,Tuck KL
,Olesnavich M
,Bhangale AD
,Walline HM
,Dermody SM
,Spector ME
,Chinn SB
,Casper K
,Mierzwa M
,Swiecicki PL
,Chad Brenner J
,Tewari M
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Extracapsular extension of neck nodes and absence of human papillomavirus 16-DNA are predictors of impaired survival in p16-positive oropharyngeal squamous cell carcinoma.
Human papillomavirus (HPV)-driven oropharyngeal squamous cell carcinomas (OPSCCs) demonstrate superior outcome compared with HPV-negative OPSCCs. The eighth edition of the American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) tumor, lymph node, metastasis (TNM) classification (TNM 2017) modifies OPSCC staging based on p16 positivity as a surrogate for HPV-driven disease. In p16-negative OPSCCs, lymph node (N) categories include extracapsular/extranodal extension (ECE); and, in p16-positive OPSCCs, N categories are based on the number of positive neck lymph nodes omitting ECE status. The objective of the current study was to assess the prognostic impact of positive ECE status and the detection of HPV16 DNA in patients with p16-positive OPSCC.
In a cohort of 92 patients with p16-positive, lymph node (N)-positive (stage III-IVB) OPSCC who underwent surgery and neck dissection, allowing for a pathologic examination of positive lymph nodes, 66 of 92 patients (71.4%) were p16-positive/HPV16 DNA-positive, 62 of 92 (67%) were ECE-positive, and 45 of 62 (72.6%) were ECE-positive, p16-positive, and HPV16 DNA-positive. Differences in outcome were assessed using Kaplan-Meier plots and Cox proportional hazard regression (CoxR) for tumor-specific survival and overall survival (OS).
The mean numbers of positive lymph nodes in ECE-positive patients (5.0 positive lymph nodes; 95% CI, 3.8-6.4 positive lymph nodes) and ECE-negative patients (2.4 positive lymph nodes; 95% CI, 1.8-2.9 positive lymph nodes) were different (P = .0007). ECE affected OS and tumor-specific survival in p16-positive patients (P = .007 and P = .047, respectively) and in p16-positive/HPV16 DNA-positive patients (P = .013 and P = .026, respectively). Related to the unequal distributions of ECE-positive/HPV16 DNA-negative tumors, the TNM 2017 failed to discriminate OS in patients with UICC stage I, II, and III disease (mean OS, 54.5, 73.4, and 45 months, respectively; median OS, 64.7 months, not reached, and 41.1 months, respectively). According to a univariate CoxR, the presence of ECE predicted impaired OS in patients with p16-positive OPSCC (hazard ratio, 3.40; 95% CI, 1.17-9.89; P = .025) and even greater impaired OS in those with p16-positive/HPV16 DNA-positive OPSCC (HR, 8.64; 95% CI, 1.12-66.40; P = .038). Multivariate CoxR confirmed ECE and HPV16 DNA detection as independent predictors.
ECE and HPV16 DNA status should be included in the prognostic staging of patients with p16-positive OPSCC because several lines of evidence demonstrate their impact on survival.
Freitag J
,Wald T
,Kuhnt T
,Gradistanac T
,Kolb M
,Dietz A
,Wiegand S
,Wichmann G
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