The quantitative analysis of the human papillomavirus DNA load in submandibular gland lesions with droplet digital polymerase chain reaction

Abstract

Background: The relationship between infection with human papillomavirus (HPV) and tumorigenesis of salivary gland remains controversial.

Objectives: This study explored the relationship between HPV and salivary gland lesions as well as that of the HPV infection status and p16^INK4A immunoreactivity. The HPV DNA loads were also quantitatively evaluated.

Materials and Methods: Tissue samples from 31 submandibular gland lesions were evaluated. p16^INK4A immunohistochemical (IHC) staining, nested polymerase chain reaction (PCR), DNA sequencing, and droplet digital PCR (ddPCR) were performed.

Results: Non-neoplastic lesion, benign tumors, and malignant tumors were noted in 9, 16, 6 cases, respectively. p16^INK4A immunoreactivity was higher in malignant tumors than in benign tumors (50.0% vs. 6.3%). Single PCR with MY09/11 found that all samples were negative. Nevertheless, nested PCR revealed a high HPV-DNA positivity rate of 96.8%. No relationship between the HPV status and p16^INK4A immunoreactivity was shown. HPV-18 was the only subtype identified in this study. ddPCR showed significantly lower HPV-18 DNA loads in submandibular gland lesions than in oropharyngeal cancers.

Conclusions: HPV-DNA positivity and p16^INK4A-immunoreactivity were not correlated in submandibular gland lesions. The loads of HPV DNA detected in this study were small. HPV positivity therefore may not be associated with tumorigenesis of the submandibular gland.

Chinese abstract

背景：感染人乳头瘤病毒（HPV）与唾液腺肿瘤发生的关系仍有争议。

目的：探讨人乳头状瘤病毒（HPV）与唾液腺病变之间的关系, 以及人乳头状瘤病毒（HPV）感染状况和p16^INK4A免疫反应性之间的关系。此外, 还定量评估了HPV染色体载量。

材料与方法：对31例颌下腺病变的组织标本进行评估。进行了 p16^INK4A免疫组化（IHC）染色、套式聚合酶链反应（PCR）、DNA测序和液滴数字PCR（ddPCR）。

结果：非肿瘤性病变9例, 良性肿瘤16例, 恶性肿瘤6例。恶性肿瘤的p16^INK4A免疫活性高于良性肿瘤（50.0% 对6.3%）。MY09/11的单次PCR结果显示所有样本均为阴性。然而, 套式PCR显示高HPV-DNA阳性率为96.8%。HPV状态与p16^INK4A免疫反应无相关性。HPV-18是本研究确定的唯一亚型。ddPCR显示颌下腺病变的HPV-18 DNA载量明显低于口咽癌。

结论：HPV-DNA阳性与p16^INK4A免疫反应性在颌下腺病变中无相关性。本研究检测到的人乳头状瘤病毒DNA载量较小。因此, HPV阳性可能与颌下腺的肿瘤发生无关。

Keywords:

• Salivary gland
• HPV
• p16
• nested PCR
• ddPCR
• DNA load

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number [JP17K11316], [JP15K10802].