November 14, 2023

p16 is a protein made by normal cells throughout the body. It can also be made by abnormal cells including some types of cancers. It is a type of protein called a tumour suppressor. This means that the normal role of this protein is to stop the cell from changing into a cancer cell.

After it is made, most of the p16 stays in a part of the cell called the nucleus. The nucleus is the part of the cell that holds most of our genetic information. Pathologists use a test called immunohistochemistry (IHC) to see p16 inside cells. The results of this test are used with other information to make a diagnosis.

In some areas of the body, p16 is considered a ‘surrogate’ marker for human papillomavirus (HPV) because cells infected with this virus produce large amounts of this protein. Precancerous and cancerous tumours associated with HPV such as high grade squamous intraepithelial lesion (HSIL) and squamous cell carcinoma frequently overexpress p16 and pathologists often perform IHC for p16 to help confirm the diagnosis.

About this article

This article was written by doctors to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

Other helpful resources

Atlas of pathology
A+ A A-