Liquid Biopsy Biomarkers for Cervical Cancer: A Systematic Review.

Cervical cancer remains a significant public health priority, particularly in low- and middle-income countries. In this context, liquid biopsy has emerged as a minimally invasive method for detecting and monitoring molecular biomarkers, offering advantages over traditional screening approaches. This systematic review included 21 studies published between 2015 and 2025 and was conducted in accordance with the PRISMA 2020 statement. The analysis examined the role of serum cytokines, circulating microRNAs (miRNAs), and circulating cell-free HPV DNA (cfHPV-DNA) in patients with cervical cancer or high-grade intraepithelial lesions. Circulating miRNAs-particularly miR-21, miR-29a, and miR-34a-are consistently associated with recurrence, tumor progression, and reduced survival. However, their immediate clinical translation remains limited by methodological variability and the lack of universal normalizers. In contrast, cfHPV-DNA, especially with ddPCR, exhibited the best study-level performance, with a specificity of 100% and a sensitivity of approximately 80-88%, across heterogeneous endpoints and analytic conditions. Consequently, cfHPV-DNA represents a promising tool for post-treatment surveillance and early detection of recurrence. Serum cytokines, such as TNF-α, IL-6, and IL-10, reflect inflammation and the tumor microenvironment. Nevertheless, their lack of standardization and variability across detection platforms restricts their reproducibility, positioning them as complementary rather than stand-alone markers. In conclusion, the evidence supports liquid biopsy as a promising tool in cervical cancer management; nonetheless, only cfHPV-DNA is currently ready for clinical application, whereas miRNAs and cytokines require multicenter validation and technical standardization before implementation.