The Use of p16 immunostaining in resolving discordance between colposcopy and biopsy in cervical cancer screening

BACKGROUND: Cervical cancer is one of the preventable cause of cancer morbidity and mortality because of availability of numerous screening procedures. Colposcopy is considered a standard for cervical diagnosis by the clinicians. But there is an imperfect correlation between the visual changes of the cervical epithelium and the severity of the preneoplastic and neoplastic changes. Colposcopy has a high sensitivity but low specificity, leading to discordance between colposcopy and biopy results, particilarly in diagnosing early lesions. p16 is a tumour suppressor protein and it inhibits cyclin dependant kinase 4 & 6, which are regulatory proteins in cell cycle. p16 is a surrogate marker for high risk human papilloma virus (HR-HPV) – mediated carcinogenesis in cervical epithelium. AIMS AND OBJECTIVES: 1. To study the use of p16 immunostaining (surrogate marker for high risk HPV) in resolving discordance between colposcopy and biopsy in cervical cancer screening. 2. To assess the use of p16 as a criteria for patient follow up. Thus p16 positive but biopsy negative cases will be kept under surveillance to look for progression of disease. METHODS: In our study group, discordant cases between colposcopy and biopsy were included. 70 patient samples consisting of chronic cervicitis (60 out of the 84 false positive cases), and all 10 false negative cases including CIN I, CIN II, CIN III, Suspicous of malignancy were included in the study. Strong nuclear and cytoplasmic expression was considered a positive reaction. RESULTS: Out of 60 chronic cervicitis cases, 58 were negative (96.6%) and 2 were positive (3.4%). Of the 4 CIN I cases, 2 were positive (50%) and 2 was negative (50%). All CIN II, CIN III, suspicious cases were positive (100%). Statistical analysis was done and CHI SQUARE = 46.04 p