Protein p^16INK4A expression in cervical intraepithelial neoplasia and invasive squamous cell carcinoma of uterine cervix

• Main Authors: Gupta Ruchi (Author), Srinivasan Radhika (Author), Nijhawan Raje (Author), Suri Vanita (Author), Uppal Radha (Author)
• Format: Book
• Published: Wolters Kluwer Medknow Publications, 2010-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 0377-4929; 0974-5130
• Keywords: p16; cervical intraepithelial neoplasia; squamous cell carcinoma; Pathology; RB1-214; Microbiology; QR1-502
• Source: Indian Journal of Pathology and Microbiology, Vol 53, Iss 1, Pp 7-11 (2010)

The association of human papilloma virus (HPV) infection and cervical intraepithelial neoplasia (CIN) is well recognized. Interaction of HPV oncogenic proteins with cellular regulatory proteins leads to up regulation of <i>p16^INK4A , a CDK inhibitor</i>, which is a biomarker for HPV infection. We investigated p16 expression in CIN and invasive squamous cell carcinoma (SCC) which has not been reported in the Indian population previously. <b> Materials and Methods: </b> Retrospective analysis of 100 cases with 20 cases each of histologically normal cervical epithelium, CIN1, 2, 3 and invasive SCC for p16 expression was performed by immunohistochemistry using commercially available mouse monoclonal antibody to p16 (clone 6H12). <b> Statistical Analysis:</b> For differences in expression among groups, statistical analysis was carried out using ANOVA and post hoc test of Scheffe.<b> Results:</b> p16 immunoreactivity was found to be both nuclear and/or cytoplasmic. The normal cervical epithelium was predominantly negative for p16 (18/20). There was a progressive increase of p16 expression with the grade of CIN. In CIN 1, two cases (20&#x0025;) showed nuclear and nucleocytoplasmic positivity respectively. In contrast, diffuse strong nuclear or nucleocytoplasmic expression was observed in 45 and 55&#x0025; cases of CIN 2 and CIN 3 respectively. All except one squamous cell carcinoma stained strongly positive for p16. The difference in expression between CIN 2/3 and SCC versus normal cervix was found highly significant (p is equal to 0.008 and p less than 0.001). <b> Conclusions:</b> p16 expression correlates excellently with the grade of CIN and is a sensitive marker of cervical intraepithelial neoplasia.