Objectives: To demonstrate the diagnostic utility of MCM-6 as a molecular biomarker for the identification of high-grade cervical disease. Methods: Thirty four pairs of cervical carcinoma and matched adjacent normal cervical epithelium specimens were obtained as fresh-frozen tissues and paraffin-embedded formalin-fixed biopsies. Fifty additional cervical histology specimens were analyzed in tissue microarray (TMA) sections. All clinical specimens were obtained with patient consent and under IRB approval. Samples were analyzed for HPV presence by PCR analysis and DNA sequencing of the L1 amplicon. mRNA expression was analyzed by TaqMan real-time RT-PCR assay. Protein expression was evaluated by Western blot analysis and by immunohistochemistry assays (IHC). Results: All 34 cervical carcinoma specimens were positive for high-risk HPV DNA and showed the following type distribution: HPV-16 (53%), HPV-18 (24%), HPV-16+18 (18%), and HPV-45 and 73 (one sample each). All cervical carcinoma specimens displayed a 3-6 fold over-expression of mRNA for MCM-6 relative to the matched normal cervical epithelium controls. Western blot analysis showed that MCM-6 protein was over-expressed in the majority of cervical carcinoma samples. No expression or very low expression was detected in the matched normal controls. Tissue IHC showed that MCM-6 was highly expressed in cervical carcinoma tissues with no expression detected in the matched normal epithelium specimens. In addition, IHC analysis on tissue microarrays of archival cervical samples revealed over-expression of MCM-6 in CIN3 and cervical carcinoma tissues. Minimal expression was observed in CIN1 and CIN2 lesions and within the proliferative parabasal layer of the cervical epithelium. Conclusions: In the present panel of cervical specimens, elevated expression of MCM-6 was observed within CIN3 and cervical carcinoma tissues. The data indicate that within this study population, MCM-6 is a specific molecular biomarker to distinguish high-grade lesions and cervical carcinoma from low-grade dysplasia and normal proliferating cells with cervical biopsy specimens.

[Proc Amer Assoc Cancer Res, Volume 46, 2005]