P16 immunostaining allows for accurate subclassification of vulvar squamous cell carcinoma into HPV-associated and HPV-independent cases

Angela S. Cheng, Anthony Karnezis, Suzanne Jordan, Naveena Singh, Jessica N. McAlpine, C. Blake Gilks

Research output: Contribution to journalArticle

24 Scopus citations


The aim of this study was to compare morphologic assessment and p16 immunohistochemistry (IHC) in the determination of human papilloma virus (HPV) status in vulvar squamous cell carcinoma (VSCC). A total of 201 invasive VSCC cases were classified as ''HPV-associated'' when warty/basaloid VSCC or high-grade squamous intraepithelial lesion (vulvar intraepithelial neoplasia 2/3) was observed, or ''HPV-independent'' in the presence of well-differentiated keratinizing invasive SCC or differentiated vulvar intraepithelial neoplasia. For p16 IHC, strong nuclear and cytoplasmic staining of all cells in at least the lowermost third of the epithelium was scored as positive. All cases with discrepant HPV predictions by hematoxylin and eosin morphology versus p16 IHC were further analyzed by polymerase chain reaction for HPV DNA. On the basis of hematoxylin and eosin morphologic assessment, 50/201 tumors showed features suggestive of HPV-associated, and 47 of those showed p16 immunoreactivity (94% concordance). Of the 146 cases considered HPV-independent based on hematoxylin and eosin, 115 (79%) showed negative p16 immunostaining. Thus 83% (162/196) concordance between morphologic assessment and p16 IHC was observed, overall. In 34 cases, where morphologic assessment and p16 IHC did not agree, HPV polymerase chain reaction agreed with p16 IHC in 32/34 (94%). The sensitivity and specificity of p16 IHC in classification of VSCC as HPV-independent or HPV-associated was 100% and 98.4%, respectively. Morphologic assessment and p16 IHC are concordant in classifying VSCC as HPV-independent or HPV-associated in a majority of cases (83%). Most of the discrepant cases are p16-positive welldifferentiated keratinizing VSCC, and HPV polymerase chain reaction supports classification of a large majority of these (94%) as HPV-associated. p16 IHC is validated as an accurate surrogate marker for determination of HPV status in VSCC.

Original languageEnglish (US)
Pages (from-to)385-393
Number of pages9
JournalInternational Journal of Gynecological Pathology
Issue number4
StatePublished - Jan 1 2016
Externally publishedYes



  • HPV
  • p16
  • Squamous cell carcinoma
  • Vulvar cancer

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Obstetrics and Gynecology

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