Immunohistochemical Expression of P16 in Cervical Lesions: An Observational Study

Introduction: Cervical cancer is the leading cancer and the predominant cause of cancer-associated deaths among women worldwide. Human papillomavirus infection is the foremost cause of cervical cancer. P16 tumor suppressor protein is overexpressed in high-risk HPV infected cells. This has led to the development of P16 as a reliable predictive biomarker to identify women with cervical dysplasia who are at risk of progressing to high-grade cervical intraepithelial neoplasia and invasive cancer. The study aimed to determine the expression pattern of P16 in lesions of the cervix. Methods: This observational study was conducted at Paropakar Maternity and Women’s Hospital, Nepal, from June 2025 to August 2025. All patients who visited the Gynecology outpatient department for abnormal cervical screening were included in the study. An immunohistochemistry test for P16 was performed in histologically confirmed pre-invasive and invasive lesions. Results: Of 88 cervical biopsies, 34 (38.63%) lesions were preinvasive, and 20 (22.72%) lesions were invasive. P16 immunohistochemistry was performed in 52 (59.09%) histologically confirmed dysplastic and invasive cervical lesions. Among 52 dysplastic lesions, 37 (71.15%) cases were P16- positive. Out of 37 P16-positive cases, 17 (45.95%) were preinvasive and 20 (54.05%) were invasive lesions. In pre-invasive group, 1 (10 %) were CIN1 lesion, 2 (28.57%) CIN II lesions, and 14 (93.33%) CIN III lesions were P16 positive, and among 20 invasive lesions, 20 (100%) were P16 positive. Conclusions: P16 expression was found to increase with the severity of cervical dysplasia and was positive in all invasive cervical cancer cases.