Detection of human papillomavirus mRNA and cervical cancer cells in peripheral blood of cervical cancer patients with metastasis

Purpose: To determine the presence of cervical cancer cells in circulating peripheral blood of stage IVb cervical cancer patients with metastasis to distant organs. Patients and Methods: Cervical cancer tissue from 15 stage IVb cervical cancer patients with metastasis were analyzed for the presence of human papillomavirus (HPV) type 16 DNA by nested polymerase chain reaction (PCR). The presence of transcriptional products of the HPV type 16 E6-transforming gene in the peripheral blood of the same 15 cancer patients was analyzed by reverse transcription and PCR. Cervical tissues and peripheral-blood specimens from 12 normal healthy individuals served as controls. Results: Thirteen of 15 (86.7%) cervical cancer tissues from same number of patients were found to contain HPV type 16 DNA. Peripheral-blood specimens from 12 of 13 (92.3%) cervical HPV DNA-positive patients were found to contain HPV-specific mRNA detectable by reverse transcription (RT) and PCR. Cervical tissues from all 12 normal controls were HPV-free. None of the peripheral-blood specimens from two cervical HPV-negative cancer patients and 12 normal controls contained detectable amounts of mRNA of HPV type 16 E6- transforming gene. Conclusion: The most likely source of the HPV-specific mRNA detected in the peripheral blood of cervical cancer patients with metastasis is the cervical cancer cells derived from or shed from the cervix. The presence of HPV E6 mRNAs in peripheral blood may be o sensitive indicator of circulating cervical cancer cells. If PCR positivity is proven to be able to predict disease progression reliably, these findings may have clinical applications in the treatment of cervical and many other cancers.