Abstract
Background: Head and neck cancers (HNCs) are a heterogeneous group of tumors that progress owing to varied enviromental and genetic risk factors. Viral infections are threatening and adept at altering the expression of cellular transcription factors such as nuclear factor kappa B (NF-kappa B) and deregulation of other cellular proteins like NF kappa B inhibitor alpha (I kappa B alpha). The present study was conducted to detect high-risk genotypes of human papillomavirus (HPV) and protein expression of NF-kappa B signaling pathway in HNC patients with HPV infection.
Methods: For HPV detection, genomic DNA from 152 HNC tumors was extracted formalin-fixed paraffin-embedded tissue DNA kit. For genotyping, polymerase chain reaction (PCR) using a general primer, HPV type-specific primers and agarose gel electrophoresis were performed. Immunohistochemistry (IHC) was also performed on 4-mu m thick tissue sections using HPV E6 monoclonal antibody. Protein expression analysis of NF-kappa B signaling pathway including p50, p65, and I kappa B alpha was performed using IHC.
Results: PCR analysis showed that 24.3% (37/152) of HNC cases were HPV positive. Among HPV positive, 86.5% (32/37) were tobacco users, while among HPV negative, 66.9% (77/115) were tobacco users. A significant association of HPV positivity and tobacco user was observed by univariate analysis [P < 0.01; odds ratio (OR): 0.310, 95% confidence interval (CI): 0.110 to 0.870]. More HPV positive patients were with poor oral hygiene (78.3%) when compared with patients with good oral hygiene (21.6%) [P < 0.03, OR: 2.440, 95% CI: 1.650 to 3.600]. The results of the logistic regression analysis showed that age, tobacco use and oral hygiene are significant predictors (P < 0.02). PCR and IHC staining results confirmed that HPV16 was predominant among HNC cases (64.8%) when compared with HPV18 (35.2%). Expression of NF-kappa B proteins (p50, p65, and I kappa B alpha inhibitor) were also observed in HPV and non-HPV infected HNC tissues. IHC expression of p50, and p65 showed nuclear staining, while I kappa B alpha inhibitor showed cytoplasmic staining. Protein expression in HPV cases was higher as compared to HPV naive cases (P < 0.05).
Conclusions: From the study, it can be established that the use of tobacco, oral hygiene, and HPV infection may be synergistically involved in modulating the expression of NF-kappa B signaling pathway for the development and progression of HNC in the Pakistani population.