title: Immunohistochemical Detection of p16(INK4a) in Leukoplakia and Oral Squamous Cell Carcinoma.
abstract: BACKGROUND
  Over-expression of p16(INK4a) has been reported in tissues of oral squamous cell carcinoma (SCC) associated with Human Papillomaviruses (HPVs). Immunohistochemical (IHC) detection of p16(INK4a) is an easy technique than molecular detection of HPVs, hence we investigated the presence of this protein in the most common pre-malignant and malignant oral lesions i.e. leukoplakia and SCC respectively.
  
  
  METHODS
  We performed IHC detection of p16(INK4a) in sections of paraffin embedded formalin fixed tissues of leukoplakia with or without dysplasia (n= 21) and SCC lesions (n= 69) and correlated with various patterns of p16(INK4a) positivity with respect to histological diagnosis.
  
  
  RESULTS
  In the present study, 71% cases of oral SCC cases were positive for p16(INK4a), of which the most common pattern was diffuse nuclear and cytoplasmic staining. Among the cases with leukoplakia, 57.1% were positive for overexpression of p16(INK4a), wherein diffuse and sporadic pattern was observed among 23.8 percent each.
  
  
  CONCLUSIONS
  In the present study, significant number of oral SCC cases observed overexpressing p16(INK4a) . However HPV DNA detection based studies are needed to validate the utility of IHC detection of p16(INK4a) as a surrogate marker for HPV associated oral SCC.
authors.affiliation: Assistant Professor, Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University , Varanasi-221005, India .
authors.forename: Pradyot
authors.initials: P
authors.lastname: Prakash
authors.affiliation: Senior Resident, Department of Pathology, Institute of Medical Sciences, Banaras Hindu University , Varanasi-221005, India .
authors.forename: Muktesh
authors.initials: M
authors.lastname: Khandare
authors.affiliation: Professor, Department of Pathology, Institute of Medical Sciences, Banaras Hindu University , Varanasi-221005, India .
authors.forename: Mohan
authors.initials: M
authors.lastname: Kumar
authors.affiliation: Professor, Department of General Surgery, Institute of Medical Sciences, Banaras Hindu University , Varanasi-221005, India .
authors.forename: Rahul
authors.initials: R
authors.lastname: Khanna
authors.affiliation: Associate Professor, Department of Community Medicine, Institute of Medical Sciences, Banaras Hindu University , Varanasi-221005, India .
authors.forename: Gyan Prakash
authors.initials: GP
authors.lastname: Singh
authors.affiliation: Professor, Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University , Varanasi-221005, India .
authors.forename: Gopal
authors.initials: G
authors.lastname: Nath
authors.affiliation: Professor, Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University , Varanasi-221005, India .
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Gulati
keywords: HPV; Oral carcinoma; leukoplakia; p16