What does p16 positive squamous cell carcinoma mean?
Abstract. Expression of p16INK4A (p16 positive) is highly correlated with human papilloma virus (HPV) infection in head and neck squamous cell carcinoma (HNSCC), however, p16-positivity is not limited to HPV positive tumors and therefore, not a perfect surrogate for HPV.
What does p16 positivity mean?
A positive result on p16 immunohistochemistry is defined as strong and diffuse nuclear and cytoplasmic staining (known as block staining). With squamous maturation and keratinization, p16 staining diminishes, meaning that some HSILs with surface maturation may not have full-thickness p16 staining.
Is p16 the same as HPV 16?
On the other hand, p16 protein overexpression is caused by viral E7 protein (11). Consequently, p16 is assumed to be an indirect marker of HPV-induced SCCHN. Several studies describe p16 protein detection as a useful marker of HPV (especially HPV-16) activity (12-15).
What is p16 in a biopsy?
A known p16 expressing head and neck SCC case was used as the positive control and sections of normal tonsil used for negative controls with each run. Staining was graded in the same manner on both biopsies and resections.
What is p16 in a cervical biopsy?
The p16 immunohistochemical (IHC) marker has been used increasingly as an adjunct to morphologic assessment of cervical biopsies in which the differential diagnoses include high-grade squamous intraepithelial lesion (HSIL) and its mimics.
Can you be p16 positive and HPV negative?
In fact, studies have shown that approximately 15% to 20% of p16 positive oropharyngeal SCC cases are HPV ISH negative. However, the features of such tumors and their clinical behavior are unknown.
What does p16 negative mean?
Oropharyngeal (p16-) cancer staging refers to TNM staging of carcinomas originating in the oropharynx that are not human papillomavirus (HPV)-associated. This system most commonly pertains to squamous cell carcinomas that tested negative for p16, an immunohistochemical proxy for HPV infection, or were not tested.
Can HSIL be p16 negative?
Diffuse p16 immunostaining pattern is the hallmark of HSIL because it correlates 100% with CIN2 and CIN3 lesions between initial biopsy and LEEP specimens, regardless of the HPV status. The negative predictive value for p16 immunoreactivity to predict cervical lesions less than high grade is almost 100% in our study.
Why is it called p16?
p16 was discovered in 1993. It is a protein with 148 amino acids and a molecular weight of 16 kDa that comprises four ankyrin repeats. The name of p16 is derived from its molecular weight, and the alternative name p16INK4a refers to its role in inhibiting cyclin-dependent kinase CDK4.
