Multistage carcinogenesis utilizing human genital cells and human papillomaviruses.

The preponderance of evidence indicates that a subset of human papillomaviruses are important etiological agents for cervical cancer. However, the necessity of other agents as well as cellular events is recognized because not all women with papillomaviruses develop cancer. Therefore, the exact role of papillomaviruses in the multistage carcinogenesis process is unclear. Regulation of specific viral genes is important to the malignant process. The current study demonstrates that human herpesvirus-6, another ubiquitous virus, can infect genital epithelial cells and upregulate the expression of relevant papillomavirus genes. Thus, it can be considered a cofactor for cancer.