What is a p16 Immunostain?

Published by Charlie Davidson on

What is a p16 Immunostain?

p16 (INK4a/CDKN2A) is a cell cycle regulatory protein that is overexpressed in cervical dysplasia related to human papilloma virus (HPV) infection. Nuclear and cytoplasmic staining is seen in dysplastic squamous cervical epithelial cells infected with HPV, but not in normal cells.

What is p16 a marker for?

p16 is a widely used immunohistochemical marker in gynecologic pathology. Strong and diffuse cytoplasmic and nuclear expression of p16 in squamous cell carcinomas (SCC) of the female genital tract is strongly associated with high-risk human papilloma virus (HPV) infection and neoplasms of cervical origin.

What does p16 staining mean?

p16 overexpression is strictly defined as continuous, strong, cytoplasmic and nuclear staining in the abnormal cells, which results in a “block” pattern of positivity.

What is p16 and ki67?

P16 is of great significance for the screening of cervical cancer, but by itself may not be sufficient for diagnosis. Ki-67 is a nuclear antigen that can be detected in the non-G0 phase of the cell cycle, marking the process of cell proliferation (5).

Is p16 positive bad?

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 block positive mean?

Positive staining is defined as “block” staining: strong nuclear and cytoplasmic expression in a continuous segment of cells (at least 10 – 20 cells); in squamous epithelium, block positivity needs to involve basal and parabasal layers.

Is p16 good or bad?

In conclusion, our study showed that alteration of p16 was one of the significant factors of a poor prognosis in SCCs of the lung, and that p16 might play an important role in some SCCs of the lung due to its high prevalence and prognostic value.

What does p16 focally positive mean?

In the vulva, p16 is positive in HPV-associated vulval intraepithelial neoplasia (VIN) but negative in VIN not associated with HPV. Similarly, HPV-associated invasive squamous carcinomas are p16-positive, whereas the more common non-HPV-associated neoplasms are largely negative or focally positive.

What does positive for dual stain p16 Ki-67 mean?

The positivity of p16/Ki-67 dual-staining also strongly indicates CIN2+ or high-grade squamous intraepithelial lesion (HSIL).

Is p16 negative good or bad?

Patients with p16 negative/HPV16 negative status had the worst survival for all sites combined as well as for OP. p16 status is an important prognostic indicator in both OPSCC and non-OPSCC and the p16 positive/HPV16 negative group is likely a distinct subgroup lacking any HPV genotype.

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.

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