P16 is a tumor suppressor gene with a molecular weight of 15.8 kDa. It is expressed in normal cells, cervical cancer, nasopharyngeal carcinoma, lung cancer, breast cancer, ovarian cancer, lymphoma, high-grade cervical intraepithelial neoplasia and tumors infected with high-risk HPV.P16 can be used as a marker for the diagnosis of cervical squamous cell lesions and the differential diagnosis of cervical squamous cell lesions.