Overexpression of p16(INK4A) as a biomarker for ASCUS in ThinPrep(TM) smear

Yeo, So Jin; Nam, Kei Hyun; Shim, Ill Koo; Kim, Tae Hee; Lee, Kwon Hae; Kim, Hyeong Mun; Cho, Hee Jung; Kwon, Kye Won

Abstract

OBJECTIVE
The overexpression of p16(INK4A) is induced by human papillomavirus (HPV) and associated with the carcinogenesis of cervical epithelia. So, immunostaining of p16(INK4A) may be useful biomarker in detecting CIN of cervix uteri in abnormal cervical lesions. The potential of p16(INK4A) as a biomarker for Atypical squamous cells of undetermined significance (ASCUS) examined in liquid-based specimens.
METHODS
We collected samples 30 cases of ASCUS in Thinprep(TM) smears between March 2003 and August 2003. 23 control Thinprep(TM) cases were included; 10 negative for intraepithelial lesions, 13 cervical squamous intraepithelial lesions. p16(INK4A) immunochemial staining was performed on 53samples. At the same time, we tested another cervical swabs of patients by the Hybrid Capture II(TM) test. The cut off value was scored positive if it contained above 5 abnormal cells with nuclear and cytoplasmic immunostaining.
RESULTS
The results of p16(INK4A) immunochemial staining comparing with one of HC II(TM) showed negative results with low kappa coefficient of 0.034. The sensitivity of p16(INK4A) immunochemial staining were 30.8% and the specificity were 82.4% respectively (p<0.01). p16(INK4A) is a useful marker for the detection of the cervical intraepithelial neoplasia but is not ASCUS.
CONCLUSION
Immunostaining of p16(INK4A) is not useful triage test in detecting abnormal lesion of ASCUS in liquid-based specimens.