Detection of P 16 ink 4 a in Non - Oro pharyngeal Head and Neck Squamous Cell Carcinoma

The incidence of HPV associated Head and Neck Squamous Cell Carcinoma (HNSCC) is increasing over the past 30 years. It is a growing public health concern. It has been reported that tissues of HPV associated HNSCCs over express p16 INK4a . Therefore p16 INK4a is used as a surrogate marker to detect HPV associated HNSCC. Immunohistochemical detection of p16 INK4a is an easy and simple technique than molecular detection of HPVs. Hence we investigated the presence of p16 INK4a in Non-Oropharyngeal (nasopharynx, hypopharynx and larynx)Squamous Cell Carcinoma (Non-OPSCC). Aims :The objectives of our study are (1)To study the association of p16 INK4a expression with Non-OPSCC, thus with the HPV. (2)To compare the p16 INK4a expression in different subsites of the Non-OPSCC. (3)To correlate the level of p16 INK4a expression with different grades of Non-OPSCC. Materials and methods :A total sample of 25 cases were analysed during the period of June 2014 toAugust 2015. We performed IHC in sections of formalin fixed paraffin embedded tissue of Non-OPSCC cases and correlated the various patterns of p16 INK4a positivity with respect to histopathological diagnosis. Results :In the present study, 80.00% of the Non-OPSCC cases were above 50 years of age. Non-OPSCC was more common in males with male to female ratio of 4:1 . 92.00% of Non-OPSCC cases were positive for p16 INK4a , of which the most common pattern was diffuse nuclear and cytoplasmic staining (76.00%). Conclusion :In the present study, increased number of Non-OPSCC cases was seen over expressing p16 INK4a (92.00%). Hypopharynx was the commonest site for p16 INK4a positivity (92.30%). Of the Non-OPSCC cases, most cases (76.00%) had diffuse pattern of p16 INK4a over expression. However, DNA detection based studies are needed to validate the utility of IHC detection of p16 INK4a as a surrogate marker for HPV associated HNSCC.