Diagnostic utility of high-risk human papillomavirus mRNA in situ hybridisation in squamous cell carcinoma of unknown primary in the head and neck and implementing American Society of Clinical Oncology guideline recommendations.

Abstract

The American Society of Clinical Oncology (ASCO)-endorsed College of American Pathologists guideline recommends high-risk human papillomavirus (HPV) testing for metastatic squamous cell carcinoma (SCC) of lymph nodes level II/III of unknown primary. Herein, the performance of HPV-RNA in situ hybridisation (ISH) in detection of HPV-related SCC is evaluated implementing the ASCO guideline recommendations. Eighty head and neck (HN) SCC fine needle aspirations, which utilized HPV-RNA ISH/P16, were evaluated at Johns Hopkins Hospital (2015-2018) to investigate their performance and concordance with histology. The results were compared to a prior study of 59 HNSCCs, which HPV-DNA ISH. Of the 80 reviewed fine needle aspirations, 65 (50 male, 15 female) were included. The mean age was 63.2±14.0years. The most common site was neck lymph nodes (47, 72.3%). Fifty-five cases (84.6%) were accompanied by concurrent core biopsy, and 48 cases (59.4%) had surgical follow-ups. HPV-RNA ISH was positive in 44 (67.7%), and P16 was strongly positive in 46 (70.8%). The HPV-RNA ISH/ P16 concordance rate was 92.3% on cytology material. The cytology/surgical concordance rate for HPV-RNA ISH was 88.9% (16/18). There was a discordance between the results in five cases (7.7%; HPV-RNA ISH-/P16+). HPV-RNA ISH is a robust and reliable method for detecting HPV-related HNSCC on cytology material showing concordance rate of 92.3% between HPV-RNA ISH and P16, which is a sensitive but non-specific marker. Compared to HPV-DNA ISH, HPV-RNA ISH reproducibly identifies HPV-related HNSCC with fewer discrepancies between cytology and histology. The findings of this study are in agreement with the ASCO recommendations.