P16
p16 is a commonly used immunostain. It can be considered a surrogate marker for HPV infection. p16, like most other "p" stains, is a nuclear stain. The antibody target is a cell cycle protein, cyclin-dependent kinase inhibitor 2A, sometimes denoted p16INK4a.
| P16 | |
|---|---|
| Immunostain in short | |
 HSIL showing the characteristic p16 staining. (WC/Nephron) | |
| Similar stains | HPV |
| Use | HSIL versus LSIL, HPV associated SCC versus non-HPV associated SCC |
| Subspeciality | gynecologic pathology, head and neck pathology |
| Normal staining pattern | nuclear and cytoplasmic |
| Positive | endometrial tubal metaplasia, cervical SCC, HPV-associated head and neck SCC, serous carcinoma of the endometrium |
Endocervical AIS showing the characteristic p16 staining.
Pattern
- Nuclear stain +/- cytoplasmic staining.
Use
- Squamous lesions of the uterine cervix - see HSIL.
- Head and neck squamous cell carcinoma, specifically human papillomavirus-associated head and neck squamous cell carcinoma.
- Increased expression in well-differentiated liposarcoma.[1]
- Limited use in melanocytic lesions.[2]
Head and neck squamous cell carcinoma
p16 testing is useful in:
- Lymph node metastases with an unknown primary - positivity suggests an oropharyngeal primary.
- Oropharyngeal carcinomas.
Note:
- Like elsewhere, i.e. other anatomical sites, p16 is an imperfect surrogate marker for the presence of HPV.[3]
- Non-oropharyngeal sites (oral cavity, larynx, and hypopharynx) are not well-studied; however, it is known that p16 positivity is much less common in there.[3]
Images
c/w HPV-assoc. SCC - p16 - intermed. mag. (WC/Nephron)
c/w HPV-assoc. SCC - p16 - high mag. (WC/Nephron)
Positive
- Squamous cell carcinoma - esp. cervical SCC, anal SCC, penile SCC, HPV-associated head and neck SCC.
- High grade urothelial carcinoma ~86% of cases by PCR.[4]
- Serous carcinoma of the endometrium - should be strong.[5]
- High-grade squamous intraepithelial lesion - full thickness, strong.
- A subset of LSIL stains with p16; however, it is not full thickness - see HSIL article.
- Small cell carcinoma of the lung - most cases (95 of 101 cases in one series[6]).
Benign
- p16 endometrial tubal metaplasia.[7]
Focal staining
- Endometriosis - focal/weak staining may be seen.[8][9]
Negative
- Lung squamous cell carcinoma[10] - 21% positive (7/33).[11]
References
- ↑ Thway, K.; Flora, R.; Shah, C.; Olmos, D.; Fisher, C. (Mar 2012). "Diagnostic utility of p16, CDK4, and MDM2 as an immunohistochemical panel in distinguishing well-differentiated and dedifferentiated liposarcomas from other adipocytic tumors.". Am J Surg Pathol 36 (3): 462-9. doi:10.1097/PAS.0b013e3182417330. PMID 22301498.
- ↑ Koh, SS.; Cassarino, DS. (Jul 2018). "Immunohistochemical Expression of p16 in Melanocytic Lesions: An Updated Review and Meta-analysis.". Arch Pathol Lab Med 142 (7): 815-828. doi:10.5858/arpa.2017-0435-RA. PMID 29939777.
- ↑ 3.0 3.1 Stephen, JK.; Divine, G.; Chen, KM.; Chitale, D.; Havard, S.; Worsham, MJ. (2013). "Significance of p16 in Site-specific HPV Positive and HPV Negative Head and Neck Squamous Cell Carcinoma.". Cancer Clin Oncol 2 (1): 51-61. doi:10.5539/cco.v2n1p51. PMID 23935769.
- ↑ Piaton, E.; Casalegno, JS.; Advenier, AS.; Decaussin-Petrucci, M.; Mege-Lechevallier, F.; Ruffion, A.; Mekki, Y. (Oct 2014). "p16(INK4a) overexpression is not linked to oncogenic human papillomaviruses in patients with high-grade urothelial cancer cells.". Cancer Cytopathol 122 (10): 760-9. doi:10.1002/cncy.21462. PMID 25069600.
- ↑ Chiesa-Vottero, AG.; Malpica, A.; Deavers, MT.; Broaddus, R.; Nuovo, GJ.; Silva, EG. (Jul 2007). "Immunohistochemical overexpression of p16 and p53 in uterine serous carcinoma and ovarian high-grade serous carcinoma.". Int J Gynecol Pathol 26 (3): 328-33. doi:10.1097/01.pgp.0000235065.31301.3e. PMID 17581420.
- ↑ "P16 is a useful supplemental diagnostic marker of pulmonary small cell carcinoma in small biopsies and cytology specimens". Ann Diagn Pathol 33: 23–29. April 2018. doi:10.1016/j.anndiagpath.2017.11.008. PMID 29566943.
- ↑ Horree, N.; Heintz, AP.; Sie-Go, DM.; van Diest, PJ. (2007). "p16 is consistently expressed in endometrial tubal metaplasia.". Cell Oncol 29 (1): 37-45. PMID 17429140.
- ↑ Stewart, CJ.; Bharat, C. (Feb 2016). "Clinicopathological and immunohistological features of polypoid endometriosis.". Histopathology 68 (3): 398-404. doi:10.1111/his.12755. PMID 26095917.
- ↑ O'Neill, CJ.; McCluggage, WG. (Jan 2006). "p16 expression in the female genital tract and its value in diagnosis.". Adv Anat Pathol 13 (1): 8-15. doi:10.1097/01.pap.0000201828.92719.f3. PMID 16462152.
- ↑ Pereira, TC.; Share, SM.; Magalhães, AV.; Silverman, JF. (Jan 2011). "Can we tell the site of origin of metastatic squamous cell carcinoma? An immunohistochemical tissue microarray study of 194 cases.". Appl Immunohistochem Mol Morphol 19 (1): 10-4. doi:10.1097/PAI.0b013e3181ecaf1c. PMID 20823766.
- ↑ Wang, CW.; Wu, TI.; Yu, CT.; Wu, YC.; Teng, YH.; Chin, SY.; Lai, CH.; Chen, TC. (May 2009). "Usefulness of p16 for differentiating primary pulmonary squamous cell carcinoma from cervical squamous cell carcinoma metastatic to the lung.". Am J Clin Pathol 131 (5): 715-22. doi:10.1309/AJCPTPBC6V5KUITM. PMID 19369633.