Identification and clinical implementation of biomarkers for cervical cancer
Abstract: Introduction of organised screening programs and prophylactic vaccination against human papilloma virus (HPV) have successfully reduced the incidence of cervical cancer globally. In Sweden, the incidence has been reduced by about 50 % since the introduction of the national screening programme in the late 1960’s. Despite these efforts, cervical cancer is still a major cause of cancer deaths globally.In order to reduce cervical cancer, the screening program should have a high participation rate and be based on a sensitive and specific screening test. About 20 % of women in Sweden do not participate in the organised screening program, and during the last years we have also seen a rise in cervical cancer cases in Sweden among women who participate in the screening program. Thus, there is a need to develop improved screening strategies that result in a higher participation rate, and are based on tests that more precisely identify women with high risk of developing cervical cancer. This includes searching for novel biological markers (biomarkers) that can be used to more accurately identify women with a high risk of developing cervical cancer.By offering women self-sampling for HPV analysis through direct mailing of sample kits with a chemically treated paper card, the FTA card, we were able to increase the participation rate in the screening program. We also found that the use of repeated self-sampling for women that were HPV positive in the primary screening sample increased the number of women detected with higher risk of cervical cancer (Paper II). Self-sampling was shown to be non-inferior to assisted sampling by midwife (Paper III). Using this sample collection device, we further investigated the association between increased risk of cervical cancer and HPV viral load (Paper V) as well as the vaginal microbiota (Paper VI). We also showed that proteins in the vaginal fluid can be studied using self-sampling and the FTA card (Paper I). Lastly, we identified plasma proteins that are associated with cervical cancer and could represent future biomarkers (Paper IV).This thesis has provided novel aspects on the present screening strategy, explored opportunities to increase the participation rate as well as examined possible future biomarkers for screening of cervical cancer.
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