P16INK4a immunocytochemistry in liquid-based cytology samples in equivocal pap smears -: Added value in management of women with equivocal pap smear

Objective To test whether p16(INK4a) immunotytochemistry (ICC) in liquid-based cytology (LBC) is useful with colposcopy in abnormal Pap smears. Study Design A series of 248 women with abnormal Pap smear were analyzed for oncogenic (HR) hu-. man papillomavirus (HPV) types using the Hybrid Capture H assay and for p(16INK4a) expression using ICC on cervical samples in PreservCyt liquid media. Colposcopic and loop electrosurgical excision pro-cedure (LEEP) cone biopsy were the gold standard. Results p(16INK4a), ICC did best as predictor of high-grade. squamous the intraepithelial lesion, with OR 12.18 (2.72-54.57) (p= 0.0001), showing 88.2% senitivity (SE), 61.9% specificis positive 14.6% SP dictive value (PPV) and 98.6% negative predictive value (NPV). In sorting discrepant cases, p(161NK4a) ICC results in 100% SE and 100% NPV in detecting cervical intraepithelial neoplasia (CIN)2 lesions among Pap+/biopsy- women. In atypical squamous cells undetermined significance (ASCUS) cytology, adding p16(INK4a) ICC improves specificity of colposcopy from 27.3% to 81.8% and PPV from 42.8% to 71.4%. Best performance is obtained with p16(INK4a) ICC and colposcopy: 83.3% SE, 81.8% SP, 71.4% PPV and 90.0% NPV. Conclusion p16(INK4a) is useful in sorting clinically relevant discrepant cases, and p16(INK4a) ICC significantly improves SP and PPV of colposcopy in management of ASCUS cytology.