Determination of high-risk HPV status of head and neck squamous cell carcinoma using the Roche cobas HPV test on cytologic specimens and acellular supernatant fluid

Abstract

Background: High-risk human papillomavirus–positive (hrHPV+) oropharyngeal squamous cell carcinomas comprise a subset of head and neck squamous cell carcinomas (HNSCCs) with a distinct biology and prognosis. Commonly, the diagnosis of HNSCC is rendered on fine-needle aspiration (FNA). Because cell blocks may be insufficient for determining HPV status using microscopy-based techniques, the ability of liquid-based assays was examined in the current study. Methods: The performance of the Roche cobas 4800 platform was evaluated on the FNA material from the cell pellet and corresponding cell-free supernatant fluid specimens of primary and metastatic HNSCCs. These results were compared with the p16 immunostain result from the histologic material obtained from the same patient. Discrepant cases were adjudicated using hrHPV RNA in situ hybridization. Results: A total of 41 samples (23 primary tumors and 18 lymph node metastases) were acquired from 34 patients with HNSCC. Primary tumors included the oropharynx (20 samples), oral cavity (13 samples), larynx (3 samples), and skin (3 samples). In 2 cases, a primary tumor could not be identified. Twenty-three samples (56%) were found to be p16 positive by immunohistochemistry. Twenty-two samples were found to be positive on cobas hrHPV testing from both cell pellet and cell-free supernatant fluid. Two cell-free supernatant fluid specimens yielded indeterminate cobas results. At the time additional hrHPV RNA in situ hybridization analysis was performed, one cobas-positive cell pellet was deemed to be a false-positive result. The sensitivity of the cobas assay was 100% for pellet material and cell-free supernatant fluid, with specificities of 94.7% and 100%, respectively. Conclusions: cobas hrHPV testing of HNSCC specimens demonstrated high concordance with p16 immunohistochemistry on the corresponding cell block and/or tissue specimen. Using the cell-free supernatant fluid in this platform could provide accurate HPV results while conserving material for cytomorphologic analyses.