Mónica Sierra-Martínez

Secretion of Extracellular Microvesicles Induced by a Fraction of Escherichia coli: Possible Role in Ovarian Cancer with Bacterial Coinfections

Ovarian cancer (OC) is usually diagnosed at an advanced stage, contributing to its high mortality rate. The presence of concurrent bacterial infections in these patients is a common clinical observation, and the mechanisms by which this coinfection influences tumor progression are still not fully understood. This study investigates the role of polydisperse extracellular vesicles (PEVs) secreted by OC cells in response to bacterial components, aiming to elucidate a potential communication pathway between OC and the bacterial microenvironment. We stimulated a human OC cell line in vitro with a fraction of E. coli. Our results show that this bacterial stimulation significantly increases the secretion of PEVs by cancer cells. A subsequent proteomic analysis of these PEVs revealed an enrichment of proteins, including filamin A, filamin B, alpha-enolase, and heat shock cognate 71 kDa protein. In addition, the PEVs displayed protease activity (on fibronectin and gelatin) and phosphatase activity against para-nitrophenyl phosphate, indicating their capacity to alter cellular signaling. This represents a novel mechanism through which bacterial coinfection may influence the biological behavior of OC if bacteria interact with tumor cells, potentially contributing to their aggressiveness and the challenges associated with their treatment. Our work highlights the importance of studying the interplay between the tumor and its associated microbiota to better understand ovarian cancer progression and identify new therapeutic targets.

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.