ProEx C immunocytochemistry and high-risk human papillomavirus DNA testing in papanicolaou tests with atypical squamous cell (ASC-US) cytology: correlation study with histologic biopsy

Abstract

Context: Papanicolaou tests with atypical squamous cells of undetermined significance (ASC-US) cytology and adjunct testing for high-risk human papillomaviruses (hr-HPV) are helpful in detecting high-grade disease. Detection of disease may be further improved with molecular markers known to be overexpressed in cervical carcinoma. ProEx C detects 2 such molecular markers, minichromosome maintenance protein 2 and topoisomerase II, which are associated with abnormal cell cycle regulation.

Objective: To determine the utility of ProEx C as a marker for high-grade cervical intraepithelial neoplasia 2+ disease when compared with hr-HPV status in Papanicolaou tests with ASC-US cytology.

Design: A SurePath slide was prepared on all ASC-US cases from the residual SurePath vial pellet and stained using the ProEx C reagent prediluted with water-bath antigen retrieval, using a Dako autostainer. Nuclear staining of cytologically atypical squamous cells was considered a positive result. Adjunct testing for hr-HPV used Digene Hybrid Capture 2. Follow-up biopsy results were available for review following the Papanicolaou test.

Results: Two hundred patients with ASC-US diagnoses were part of this study. The sensitivities of ProEx C and hr-HPV testing in detecting high-grade cervical intraepithelial neoplasia 2+ disease were 98.04% and 82.35%, respectively, whereas the specificity for detecting high-grade disease was 74.50% and 73.15%, respectively.

Conclusions: ProEx C staining is a more sensitive and specific biomarker for detecting cervical disease than adjunct testing for hr-HPV status in Papanicolaou tests with ASC-US.