Detection of survivin expression in cervical cancer cells using molecular beacon imaging: new strategy for the diagnosis of cervical cancer.

OBJECTIVE Development of novel approaches for quantitative analysis of gene expression in intact tumour cells could provide new methods for the detection of cervical cancer. Molecular beacons (MBs) are single-stranded oligonucleotide probes that form stem-and-loop structures. Survivin, a member of the 'inhibitor of apoptosis' family of proteins, is highly expressed in cervical cancer. The aim of this study was to determine the feasibility of MBs targeting wild-type survivin in the diagnosis of cervical cancer. STUDY DESIGN MBs with oligonucleotide sequences complementing survivin mRNA and covalently linked with FITC or Cy3 were designed and synthesized. The specificity and sensitivity of survivin MBs were examined in human cervical cancer cell lines and smears from cervical cancer patients, and confirmed by reverse transcriptase polymerase chain reaction (RT-PCR), immunocytochemistry, Western blotting and the thinprep cytological test (TCT). RESULTS Both survivin MB-FITC and MB-Cy3 produced a strong fluorescent signal in cervical cancer cells, and the intensity was consistent with the results from RT-PCR, Western blotting and immunocytochemical staining. In the initial clinical cohort study, the sensitivity of survivin MBs was 61.37% (27/44) and the specificity was 72.72% (34/44); the sensitivities of Western blotting and TCT were 76.1% (32/42) and 68.19% (30/44), respectively. No significant difference in sensitivity was observed between MBs, Western blotting and TCT for different tumour grades and International Federation of Gynecology and Obstetrics (FIGO) stages. CONCLUSIONS Survivin MBs are specific and sensitive molecular probes for the detection of cervical cancer cells. They have great potential in the early detection and follow-up of patients with cervical cancer.