Longitudinal clinical evaluation of a novel antibody cocktail for detection of high-grade squamous intraepithelial lesions on cervical cytology specimens

Context.-Although cervical cancer screening by cytology is successful, the test continues to show relatively poor operating characteristics. Cell cycle markers may enhance detection of high-grade squamous intraepithelial lesions. Objective.-To determine the clinical usefulness of ProExC, an immunocytochemical assay for cell cycle components, performed on routine cervical cytology samples. Design.-Cervical cytology samples were collected using the SurePath method. Residual cells remaining after preparation of the Papanicolaou-stained slide were used to make a second slide for ProExC staining using an indirect polymer-based immunoperoxidase method. Only adequately cellular slides were evaluated for the presence of nuclear staining within cytologically abnormal epithelial cells. Results were correlated with clinical follow-up. Results.-Six hundred twenty-four samples were satisfactorily cellular and stained. Correlation with clinical follow-up for subsequent cervical intraepithelial neoplasia 2+ on biopsy/high-grade squamous intraepithelial lesion on cytology (CIN 2+/HSIL) showed that 434 results were true negative, 78 true positive, 18 false-negative, and 94 false-positive, resulting in a sensitivity/specificity of 81%/82%. When ProExC results were combined with any level of cytologic atypia, sensitivity for CIN 2 +/HSIL was 92% and specificity was 84%. Conclusions.-ProExC shows promise as an aid in enhancing the sensitivity and specificity of cervical cytology for subsequent CIN 2+/HSIL and may be useful in identifying those cervical lesions most apt to progress.