Can Digital Droplet PCR (ddPCR) on Blood Samples From Patients With HPV Related Cancers Become a Reality in Cancer Treatment and Monitoring?

This study hypothesises that in patients with HPV-related cervical cancer, HPV DNA may be released into the bloodstream from tumor cells. These fragments of HPV DNA shed by tumor may therefore be measured in blood samples from the patients. By using the same setting as for real-time PCR with PCR primers and probes for fluorescence detection, the study uses digital droplet PCR (ddPCR), a method based on dilution and partitioning of the blood sample in many reaction chambers or droplets, to measure absolute quantities of HPV DNA fragments in blood samples from women with different stages of cervical cancer. Furthermore, our research group has developed in-house amplicon-based Next Generation Sequencing (NGS) assays for HPV detection and genotyping (the NGS HPV genotyping panel) and HPV integration status and variants (the HPV16 panel), and blood samples are also analysed with the NGS HPV genotyping panel. Cervical tissue samples from primary tumor are collected and analysed with the NGS HPV genotyping panel, and HPV16 positives are further analysed with the NGS HPV16 panel. Patients are recruited at the time of diagnosis, where a baseline blood sample is collected. Follow-up blood samples are collected during treatment and at follow-up visits up to two years after the diagnosis. We expect the HPV DNA load to decrease after treatment, and if an increase in viral load is detected during follow-up, we expect this to be an early sign of a disease recurrence. The method may therefore become an effective monitoring tool in these patients in terms of detecting a ongoing disease recurrence, which gives us the chance to intervene and treat these patients before the disease becomes too disseminated.

For included patients experiencing af recurrence of their disease, tissue samples from recurrent disease are collected and analysed with both the NGS HPV genotyping panel, the NGS HPV16 panel (for HPV16 positives), p16 staining, and a panel detecting relevant somatic mutations in the TP53 and RB1 tumor suppressor proteins.