Abstract: Ovarian cancer is one of the most common malignant tumors in gynecology. In early stage, patients usually don’t have any symptoms. So when it was diagnosised, the cancer often had transferred to other tissues. And it always made bad influence to the treatment. Therefore, it is important to find new biomarkers which contribute to the diagnosis of ovarian cancer in the early stage. Based on other researches, the aberrant DNA methylation has been associated to the ovarian cancer, including the diagnosis in early stage, treatment and prognosis. The methylation of cell-free DNA which come from the tumor cells maybe a kind of important biomarkers of ovarian cancer. This review is telling about the newest researches and the use in ovarian cancer.

Key words: Cell-free DNA, DNA methylation, Ovarian cancer, CpG island