title: p16 and p53 in HPV-positive versus HPV-negative oral squamous cell carcinoma: do pathways differ?
abstract: BACKGROUND
  p16 overexpression and wild-type p53 expression are associated with human papilloma virus (HPV) in cervical and oropharyngeal cancer. Role of HPV-related carcinogenesis in the etiology of oral squamous cell carcinoma (OSCC) is still vague in Indian population. We aimed to explore the expression pattern of p16 and p53 in HPV-positive and HPV-negative OSCC to elicit differences, if any. Further their effect on survival of patients was studied.
  
  
  METHODS
  Thirty-one consecutive HPV-positive as well as 31 age and sex-matched HPV-negative OSCC cases from a case series of 369 histologically diagnosed cases of OSCC were included in this study. HPV was detected by two methods, viz. real-time PCR and conventional PCR in biopsy samples. p16 and p53 protein expression was assessed by immunohistochemistry, and p16 mRNA expression was quantified with real-time PCR using SYBR Green assay.
  
  
  RESULTS
  p16 was expressed in six (19.4%) HPV-positive and in four (12.9%) HPV-negative cases. Overall mutant-type p53 expression in 62 OSCC cases was 54.8%. Out of ten p16-positive cases, eight expressed mutant-type p53 and only two cases expressed wild-type p53. Risk factors including oral tobacco consumption and alcohol were present in all these ten p16-positive cases. Survival of patients was not affected by HPV, p16 and p53 status.
  
  
  CONCLUSIONS
  Presence of mutant-type p53 and exposure to tobacco-related risk factors in both HPV-positive and negative cases suggest existence of p53-related carcinogenesis in HPV-positive cases in Indian population.
authors.affiliation: Department of Pathology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, UP, India.|Department of Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, UP, India.
authors.forename: Vineeta
authors.initials: V
authors.lastname: Singh
authors.affiliation: Department of Pathology, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, UP, India.
authors.forename: Nuzhat
authors.identifier: http://orcid.org/0000-0003-1831-9063
authors.initials: N
authors.lastname: Husain
authors.affiliation: Department of Surgical Oncology, King George's Medical University, Lucknow, UP, India.
authors.forename: Naseem
authors.initials: N
authors.lastname: Akhtar
authors.affiliation: Department of Biotechnology, Babasaheb Bhimrao Ambedkar University, Lucknow, UP, India.
authors.forename: Mohammad Yahia
authors.initials: MY
authors.lastname: Khan
authors.affiliation: Department of Surgery, King George's Medical University, Lucknow, UP, India.
authors.forename: Abhinav A
authors.initials: AA
authors.lastname: Sonkar
authors.affiliation: Department of Surgical Oncology, King George's Medical University, Lucknow, UP, India.
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
mesh_terms: D000328:Adult; D053898:Biosynthetic Pathways; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000821:virology*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000821:virology*; D027383:Papillomaviridae / Q000302:isolation & purification*; D011446:Prospective Studies; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*
chemical_list: C000614131:CDKN2A protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D016159:Tumor Suppressor Protein p53
keywords: human papilloma virus; oral squamous cell carcinoma; p16; p53