In situ hybridization signal patterns in recurrent laryngeal squamous papillomas indicate that HPV integration occurs at an early stage

HPV RNA in-situ hybridization as a diagnostic aid in papillary laryngeal lesions

OBJECTIVES

In the larynx, differentiating squamous papillomas from de-novo papillary squamous dysplasias or squamous cell carcinomas (SCC) has significant consequences for management. Overlapping clinical presentations and cytologic changes across the spectrum of papillary lesions presents diagnostic challenges for otolaryngologists and pathologists. In this study, we evaluate whether ribonucleic acid (RNA) in-situ hybridization (ISH) for low-risk and high-risk human papillomavirus (HPV) can help distinguish these lesions.

METHODS

We constructed tissue microarrays from 97 papillary laryngeal lesions, including 61 squamous papillomas, two papillomas with dysplasia, two SCCs-ex papilloma, 14 papillary squamous dysplasias, and 18 papillary SCCs identified at the Johns Hopkins Hospital between 2000 and 2017. We performed RNA ISH using probes for low-risk and high-risk HPV types.

RESULTS

Low-risk HPV RNA was identified in 55 benign papillomas (90%), two papillomas with dysplasia (100%), and two SCCs-ex papilloma (100%) but was absent in de-novo papillary dysplasias and SCCs (0%). High-risk HPV RNA ISH was positive only in four papillary SCC (22%). Overall, low-risk HPV RNA ISH was 90% sensitive and 89% specific for benign papillomas with a positive predictive value of 93% and negative predictive value of 84%. In contrast, high-risk HPV was 20% sensitive for SCC.

CONCLUSION

Low-risk HPV RNA ISH is a useful diagnostic adjunct for distinguishing laryngeal squamous papillomas from papillary squamous dysplasia and SCC. However, it is not entirely specific for benign processes as it is also retained in papillomas with dysplasia and SCCs-ex papilloma. Because high-risk HPV is rare in papillary laryngeal lesions, high-risk HPV RNA ISH has limited utility.

LEVEL OF EVIDENCE

Level 4 Laryngoscope, 130:955-960, 2020.

Viral load and mRNA expression of HPV type 6 among cases with recurrent respiratory papillomatosis

OBJECTIVES/HYPOTHESIS

To determine viral load of human papillomavirus type 6 (HPV6), physical state of HPV6-DNA, and transcription level of HPV6 E7-mRNA in laryngeal papilloma and in adjacent healthy mucosa.

STUDY DESIGN

Case series.

METHODS

A papilloma biopsy was collected from each of 25 adult patients with respiratory recurrent papillomatosis. From 14 of the 25 patients, we first collected a biopsy from healthy mucosa of the false vocal fold and another from the papilloma. Quantity of HPV6 and E7-mRNA was measured by polymerase chain reaction.

RESULTS

For the papilloma, the median load of HPV6 was 41 copies/cell, and the lowest amount was 5.4 copies/cell. Human papillomavirus type 6 was detected in 50% (7/14) of the healthy mucosa, with a median of 1.1 copies/cell, and the highest amount was 6.6 copies/cell. Overall, viral load was higher in papilloma than in healthy mucosa (P < 0.05). The average HPV6 E2/E7-DNA ratio was 1.3, indicating an episomal state. Human papillomavirus type 6-mRNA was detected in all HPV6-DNA-positive samples. The transcription median ratio of HPV6-mRNA/HPV6-DNA was 1.5 in papilloma and 3.8 in healthy mucosa.

CONCLUSION

The amount of HPV6-DNA was consistently higher in the papilloma than in healthy mucosa. The transcription level of HPV6 E7 mRNA was similar in the papilloma and in normal mucosa. We suggest that interfering with replication of HPV6 and suppression of HPV6 to fewer than five copies/cell may be curative.

Human papilloma virus (HPV) is not implicated in the etiology of Warthin's tumor of the parotid gland

CONCLUSION

The lack of human papilloma virus (HPV) sequences as well as potential HPV-activated cells such as cells that would be p16- and Ki-67 positive does not support a role of HPV in the pathogenesis of this lesion.

OBJECTIVE

The exact etiopathogenesis of Warthin's tumor of the parotid gland is still unclear. The aim of the present study was to evaluate if HPV could play a role in the development of this parotid lesion.

METHODS

Tissue samples from 40 Warthin's tumors of the parotid gland were investigated by PCR followed by in situ hybridization. The immunohistochemical expression of p16 and the dual immunostaining of p16 and Ki-67 were evaluated in all samples.

RESULTS

Strong and diffuse p16 immunoreactivity was found in 7 of the 40 cases (17.5%). In situ hybridization showed a diffuse episomal signal in those samples. However, PCR could not reliably detect the presence of HPV genes. Furthermore, p16-expressing epithelial cells were mostly negative for the proliferation marker Ki-67.