Detecting genotypes of human papillomavirus with high risk for development of cervical cancer
High-risk (cancer-causing) HPV causes cervical cancer. Research studies suppose high-risk HPV is found in 100% of cases of cervical cancer. However, non-HPV cervical cancers are caused by 10% by small-cell carcinoma and by 10% by adenocarcinoma. It is not clear whether HPV can really be absent in cancerous tissue or merely may not be detected by HPV tests due to their low sensitivity.
Two different assumptions prove non-HPV cervical cancer is possible. The first one is based on the assumption that a person does not develop a cervical cancer without the virus but is induced by another pathogen. The second assumption supposed viral transforming effect of cells. Viral DNS is integrated with cellular gene causing its destabilization. During uncontrolled division of transformed cells integrated viral DNA division takes place. This causes development of tumour.
Opponents of non-HPV cervical cancers think that HPV tests used were not sufficiently sensitive to the HPV virus since they do no detect all types of virus. In the international practice, HPV tests are done by polymerase chain reaction (PCR) with universal primers (GP5+/GP6+ or SPF). Low-risk (causing warts) and high-risk (causing cancer) HPV are detected. Hybridisation is used to detect type of the virus. Analytic detection sensitivity is quite high but varies depending on the type of HPV. Different type of viruses may be competitive due to low and high concentration. That means that when in sample high-risk type 18 HPV is less in amount then low-risk type 73 HPV, the type 18 HPV may not be detected while the type 73 HPV may be recognized as the reason for cervical cancer by mistake and considered as cancer-causing. To avoid such a mistake, in detection and determination of certain HPV genotypes usage of PCR with type-specific primers is preferred.
The goal of investigation is to assess popularity of different types of high-risk HPV is the samples obtained from cervical epithelium with dysplasia of different stage of severity and in primary cancer.