Diagnostic and clinicopathological significance of Ki67 mRNA expression in cervical cancer tissue

Ki67 is a key biomarker associated with cancer cell proliferation and poor prognosis. We previously evaluated the diagnostic potential of quantitatively measured Ki67 mRNA levels in formalin-fixed paraffin-embedded (FFPE) cervical cancer tissue samples. In the present study, we continued this avenue of research using quantitative reverse transcriptase PCR (RT-qPCR) to measure Ki67 mRNA levels in FFPE cervical tissues and performed an assessment with each clinical prognostic factor of patients. We obtained 190 FFPE cervical tissue samples that comprised of 80 squamous cell carcinoma (SCC), 10 adenocarcinoma (ADC), 30 HSIL, 30 LSIL, and 40 normal cervical tissue samples. And using this assay, we also evaluated the predictive value of Ki67 in cases with a lowgrade squamous intraepithelial lesion (LSIL) and those with a high-grade squamous intraepithelial lesion (HSIL). As a result, Ki67 mRNA levels were increased in SCC and ADC cervical cancer tissues (n = 90) compared to those in normal cervical tissues (n = 40) (P < 0.001). The diagnostic validity of the Ki67 mRNA assay was evaluated and demonstrated a sensitivity of 93.3% (95% confidence interval (CI) = 86.1 to 97.5) and a specificity of 97.5% (95% CI = 86.8 to 99.9). Ki67 mRNA positivity was 93.3% for cervical cancer, 40.0% for HSIL, 13.3% for LSIL, and 2.5% for normal tissue samples. Furthermore, we found that high levels of Ki67 mRNA expression in cervical cancer were associated with lymph node status (P = 0.01). In conclusion, Ki67 mRNA assay can provide an additional accurate approach for molecular diagnosing cervical cancer, and also predict prognosis of cervical cancer depending on LSIL and/or HSIL status.