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.
To determine the clinical usefulness of ProExC, an immunocytochemical assay for cell cycle components, performed on routine cervical cytology samples.
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.
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%.
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.