The Expressions of p16, HPV16-L1 and HPV18-E6 in Salivary Gland Tumours.

AIMS

This study aimed to investigate the relationship between human papillomavirus (HPV) infection and the development of salivary gland tumour (SGT) by evaluating the expression of p16 and the oncoproteins HPV16-L1 and HPV18-E6 using immunohistochemical (IHC) staining. Additionally, we assess the agreement between these oncoproteins and p16 in diagnosing HPV-infected SGT.

METHODS

This cross-sectional study included all SGT cases undergoing surgical resection at Hospital Universiti Sains Malaysia (HUSM) and Hospital Raja Perempuan Zainab II (HRPZ) in Malaysia from April 2022 to April 2023. IHC staining was performed on paraffin-embedded tissues at the Pathology Laboratory, HUSM, to evaluate the expression of p16, HPV16-L1, and HPV18-E6 oncoproteins. The clinicopathological data were correlated with the staining results.

RESULTS

49 SGT cases were identified, mainly in middle-aged Malay women, with most tumours originating from the parotid gland. Malignant tumours included mucoepidermoid carcinoma (22.4%), adenoid cystic carcinoma (4.1%), acinic cell carcinoma (4.1%), and adenocarcinoma (2%). Benign tumours primarily consisted of pleomorphic adenoma (49%) and Warthin tumours (16.3%). Positive p16 expression was detected in 67% of cases, while HPV16 and HPV18 were detected in 65% and 90% of tumours, respectively. HPV16-L1 exhibited 75.8% sensitivity and 56.3% specificity, while HPV18-E6 showed 100% sensitivity and 31.2% specificity compared to p16.

CONCLUSION

The study findings suggest a correlation between the presence of high-risk HPV types 16 and 18 and the development of SGT, as evidenced by the overexpression of p16, HPV16-L1, and HPV18-E6 oncoproteins. Both HPV16-L1 and HPV18-E6 tests are acceptable, reliable, and sensitive for detecting high-risk HPV in SGT.