Correlation between Methylation in Cell-Free DNA and the Prognosis of Cancer Patients: A Systematic Review and Meta-Analysis.

Background: Although the effects of methylation of the Ras association domain-containing protein 1 isoform A () gene in cell-free DNA on the outcomes of patients with different types of cancer have been reported, the results are inconsistent.

Objective: : To explore the relationships between methylation in cell-free DNA and the outcomes of cancer patients.

Methods: The PubMed, Embase, and Web of Science databases were searched for papers related to this topic on December 8, 2021. The retrieved articles were screened by two independent researchers, following which the methodological quality of the selected studies was evaluated using the Newcastle-Ottawa Scale. Additionally, hazard ratios were calculated, and publication bias of the studies was determined using Egger's test.

Results: Nine relevant publications involving a combined total of 1254 patients with different types of cancer were included in this study. The combined results of the random effects models yielded a hazard ratio of 1.73 (95% confidence interval: 1.31, 2.29; < 0.001), which suggested there was a significant association between methylation and overall survival, and patients with an methylation status had a significantly increased risk of total death. Moreover, the Egger test result suggested there was no significant publication bias among the included studies.

Conclusions: The methylation of in cell-free DNA in cancer patients was observably associated with an increased risk of poor overall survival.