Comparison of Polymerase Chain Reaction and Immunohistochemistry Assays for Analysing Human Papillomavirus Infection in Oral Squamous Cell Carcinoma.

Introduction: Polymerase Chain Reaction (PCR) and Immunohistochemistry (IHC) are two well-known techniques used for the diagnoses of genetic diseases, tumours and different pathogens. PCR basically amplify regions of DNA within a single molecule which may have etiologic significance, it is a method for in vitro amplification of specific DNA or RNA sequences, whereas IHC is used to verify tissue constituents (the antigens) with the utilization of specific antibodies that can be visualized through staining.

Aim: To compare and analyse PCR and IHC for their sensitivity to detect Human Papillomavirus (HPV) in Oral Squamous Cell Carcinoma (OSCC).

Materials And Methods: This study was based on samples retrospectively collected from 47 patients with primary OSCC who were diagnosed and treated at The Aga Khan University Hospital, Karachi, Pakistan, during the period of January 2010 to December 2013. Inclusion criteria were complete clinicopathologic data, adequate clinical follow up and availability of sufficient paraffin- embedded tumour material. HPV general and type specific 16 and 18 were investigated by means of PCR. HPV immunoreactivity was further investigated by means of IHC.

Results: Among the 47 evaluated patients, 32 (68.1%) were male and 15 (31.9%) were female, PCR detected the presence of HPV in 32 (68.1%) patients while IHC showed no positive test results. p53 was positive in 32 (68.1%) patients and negative in 15 (31.9%). HPV type 16 being most prevalent showing positivity in 27 (57.4%) patients whereas, type 18 was positive in only 1 (2.1%) patient.

Conclusion: We concluded that PCR is more sensitive and reliable when diagnosing and detecting HPV for OSCC rather than IHC as results from IHC were all negative and insignificant, hence PCR should be the first initial diagnostic test for detecting HPV due to its better sensitivity and successful detection of HPV.