[1020] Does Basal Atypia in Early Cervical Intraepithelial Neoplasia Belong to High Grade Squamous Intraepithelial Lesion?

Y Lee, S Park, J Choi, JJ Lee, K-R Kim. University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea

Background: Basal atypia (BA), defined as a significant cellular atypia confined to lower layer of the cervical epithelium, was proposed as an important criterion to diagnose high grade squamous intraepithelial lesion (HSIL), however, in a CIN classification system the lesion with BA can be classified as a grade 1. Diagnosis of the lesion with BA is challenging because of the discrepancy between the two classification system. Recently, there were several manuscripts that ProExC could be a reliable marker for high grade CIN, and CIN 2 cases in which moderate to strong immunoexpression of p16 were observed simultaneously progressed to CIN 3.
Design: Early CIN (CIN 1 or 2) with BA (n=44, group 1) and CIN 1 or condyloma without BA (n=33, 16 exophytic and immature condyloma , 17 CIN 1, group 2) were retrieved during the period 2000-2008. Immunohistochemistry (p16 and ProExC) and HPV PCR were done and we analyzed expression pattern of biomarkers (p16 and ProExC) and compared those with HPV types to define the meaning of BA and to test the utility of biomarkers. Cases were scored positive for p16 if moderate to strong diffuse or focal staining was present.
Results: The group 1 showed immunopositivity for p16 in 91% and strong immunopositivity for ProExC in the lower and upper halves of the epithelium was observed in 98%. HPV PCR data were available only in 26 cases, but high risk HPV was identified in 100%. Immunopositivity for p16 and ProExC were 89% and 100%, respectively, in high risk HPV group. The group 2 showed immunopositivity for p16 in 42% and ProExC immunopositivity were seen mainly in lower half layer with scattered several positive cells in upper half of the epithelium. HPV PCR data were available only in 23 cases; low risk-HPV related lesions (n=8), high risk-HPV related lesions (n=15). The p16 immunopositivities in low risk-HPV and high risk-HPV related lesions were 0% and 87%, respectively.
Conclusions: High rate of p16 overexpression and ProExC expression pattern in the group 1 suggests that they belong to HSIL although the atypia is confined to the lower layer of the epithelium. Those two combined biomarkers were useful to detect and diagnose the lesion with BA as HSIL.
Category: Gynecologic

Monday, March 9, 2009 1:00 PM

Poster Session II # 133, Monday Afternoon