Human Papillomavirus DNA Detection by Droplet Digital PCR in Formalin-Fixed Paraffin-Embedded Tumor Tissue from Oropharyngeal Squamous Cell Carcinoma Patients.
Mol Diagn Ther 2020;
25:59-70. [PMID:
33245553 DOI:
10.1007/s40291-020-00502-6]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2020] [Indexed: 02/08/2023]
Abstract
INTRODUCTION
High-risk human papillomavirus infection impacts staging and prognosis of oropharyngeal squamous cell carcinomas (OPSCCs). Determination of HPV status in tumor tissue by p16-immunohistochemistry (p16-IHC) can be challenging; therefore, complementary methodologies could be useful in a clinical setting.
OBJECTIVE
To test for accuracy and clinical relevance of HPV-DNA detection in formalin-fixed and paraffin-embedded (FFPE) tumor samples by droplet digital PCR (ddPCR).
MATERIALS AND METHODS
Fifty OPSCCs were tested for p16-IHC status followed by HPV-16/18 DNA detection/quantification in FFPE-recovered DNA using ddPCR. Accuracy for HPV status determination and association with patient information were also evaluated.
RESULTS
32.0% (16/50) of the cases were p16-IHC positive (p16 +), 42.0% (21/50) had detectable levels of HPV-16 DNA, and none were positive for HPV-18 DNA. A higher median viral load of HPV-16 DNA was observed in p16 + cases (p < 0.0001). Concordance between p16-IHC and HPV-16 DNA ranged from 78.0 to 86.0% and accuracy rates were between 78.0 and 86.0%. P16-IHC and HPV-16 DNA detection was associated with gender, smoking status, and tumor subsite, while only HPV-16 DNA was associated with cT stage. The combination of HPV positivity by p16-IHC and ddPCR showed higher overall survival rates in comparison with p16 + /HPV-DNA- and p16 - /HPV-DNA- results.
CONCLUSIONS
Type-specific HPV-DNA detection by ddPCR is highly specific but moderately sensitive for the determination of HPV status and showed clinical relevance, mainly when associated with p16-IHC status. Results highlight the importance of performing HPV-DNA testing in combination with p16-IHC for proper identification of HPV-associated OPSCC and to improve clinical management of OPSCC patients.
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