Relevance of Partial p16 Immunostaining in Oral Squamous Cell Carcinoma and Co- Relation with HPV DNA Status

Naz, Farhat; Tanveer, Nadeem; Verma, Hitesh; Sudheer, Kumar Arava; Kakkar, Aanchal; Ranjan, Amar; Chopra, Anita; Tanwar, Pranay

doi:10.31557/APJCP.2023.24.12.4093

Relevance of Partial p16 Immunostaining in Oral Squamous Cell Carcinoma and Co- Relation with HPV DNA Status

Document Type : Research Articles

Authors

¹ Laboratory Oncology, Unit, DR. BRA IRCH, All India Institute of Medical Sciences, AIIMS- Delhi, New Delhi, India.

² Department of Pathology, University College of Medical Sciences: Delhi, Delhi, India.

³ Department of ENT, Teaching Block, All India Institute of Medical Sciences, AIIMS- Delhi, New Delhi, India.

⁴ Department of Pathology, Teaching Block, All India Institute of Medical Sciences, AIIMS- Delhi, New Delhi, India.

10.31557/APJCP.2023.24.12.4093

Abstract

Introduction: Immunostaining criteria for p16 positivity in oropharyngeal squamous cell carcinoma have been laid down by College of American Pathologists (CAP) and the American Society of Clinical Oncology (ASCO). The staining should be of moderate to strong intensity seen in 70 percent of the tumor cells. Recent studies have pointed out that a small minority of cases are missed using p16 as the surrogate marker at above mentioned cut off. By convention the same criteria have been used for oral squamous cell carcinoma. Material and Methods: The authors revisited the results of their previous study where immunohistochemistry for p16 was found to be positive by AJCC criteria in 139 out of 800 cases of oral squamous cell carcinoma. For this study, all the p16 immunonegative cases (by AJCC criteria) were analysed again for partial staining patterns, defined for this study as cases with 50-75% cells showing 2+/3+ intensity of nuclear p16 immunostaining and for basal predominant pattern of immunostaining. These cases were subjected to HPV DNA PCR. Results: Out of the 661/800 cases found to be negative for p16 immunohistochemistry, a total of 34/800(4.25%) showed partial staining based on the criterion of 50-75% cells showing p16 immunostaining intensity of 2/3+.The basal predominant pattern of immunostaining for p16 was seen in 43/800 (5.38%) cases. When these cases were subjected to HPV DNA analysis, 11/34 (32.35%) of the cases showing partial staining and 02/43 (4.7%) of the cases showing basal predominant pattern of p16 immunostaining were found to be HPV-DNA positive. Conclusion: The inclusion of partial immunostaining patterns of p16 in HPV analysis of oral squamous cell carcinoma can improve our understanding of HPV driven oral squamous cell carcinoma.

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