Reactive oxygen species within the vaginal space: An additional promoter of cervical intraepithelial neoplasia and uterine cervical cancer development?

Uterine cervical intraepithelial abnormalities and cancer development may also depend upon biological problems that arise as a result of complex molecular disturbances within the vaginal space, in addition to the widely known causative effect of human papillomavirus (HPV) infection. Chronic oxidative stress is a consequence of oxygen reduction in the vaginal space. Reactive oxygen species (ROS) and free radicals are yet unrecognizable causative agents and are probably very important factors for cervical intraepithelial neoplasia (CIN) and cancer development. The intermediate compounds of oxygen reduction on these metabolic pathways are superoxide anion (O2˙-), hydrogen peroxide (H2O2), hydroxide ions (OH-), and hydroxyl radical (HO˙). Considering these points, the aim of this work was to summarize how these compounds can damage all molecules, including DNA, of vulnerable metaplastic cervical epithelium. Finally, in some women with a poor immune defense system, ROS alone or accompanied by a high-risk HPV type may promote all levels of CIN and cancer development.