Immunocytochemical detection of raf kinase inhibitor protein and human papillomavirus profiling of normal and abnormal cervical ThinPrep samples.

OBJECTIVES: This study investigates the potential value of Raf kinase inhibitor protein (RKIP) as a marker of normal squamous cells in ThinPrep slides. RKIP was evaluated for its ability to distinguish between normal and abnormal cervical samples in the context of human papillomavirus (HPV) infections.

STUDY DESIGN: A total of 316 ThinPrep samples were taken from women with normal and abnormal cervices. ThinPrep slides were Papanicolaou stained and reported. Residual samples were used for RKIP immunostaining and HPV PCR-based sequencing.

RESULTS: RKIP expression was seen in both nuclei and cytoplasm in 83.7% of samples. RKIP expression was highest (84.6%) in samples with a diagnosis of high-grade squamous intraepithelial lesion (HSIL) or worse; expression was lower in low-grade squamous intraepithelial lesions (73%) and was lowest in samples with normal cytology (p = 0.0023). A total of 74% of HPV-infected ThinPrep samples were immunopositive, and 67% of samples that did not harbor HPV were also immunopositive (p = 0.414). Sensitivity and specificity of RKIP were 84.6 and 34.6%, respectively, for the detection of samples with HSIL or worse.

CONCLUSIONS: This study showed that RKIP expression may be of some value as a marker for abnormal cervical cells. Combined RKIP expression and HPV testing could improve the identification of samples with abnormal cytology.