Evaluating the Performance of p16

Purpose When used for cervical cancer primary screening, liquid-based cytology (LBC) has a high specificity but a low sensitivity. For histological diagnosis of high-grade lesions, p16INK4a immunostaining has proven to be useful. Therefore, our objective was to evaluate the use of p16INK4a immuno-cytology as a primary screen and a secondary screen after primary high-risk human papillomavirus (hrHPV) screening or LBC screening. Methods A total of 1197 cytology slides were immuno-stained using automatic p16INK4a staining system (PathCIN®p16INK4a) in two studies from cervical screening programs. In the primary screening study, 875 slides were randomly selected and analyzed for p16INK4a. In the secondary screening study, 322 of the remaining slides were chosen by virtue of being HPV 16/18+, other hrHPV+/LBC≥ASC-US, or HPV-negative/LBC ≥LSIL. The sensitivity and specificity for detection of cervical intraepithelial neoplasia 2/3 or worse (CIN2+/CIN3+) were compared based on p16INK4a, LBC and HPV test results. Results In combining two studies, there were 431 cases with biopsy pathology. They included 83 cases with CIN2+ and 41 cases with CIN3+. The p16 positivity rate increased with pathologic and cytologic severity (P