{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T12:00:19Z","timestamp":1789992019598,"version":"4.0.1"},"reference-count":36,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,9]],"date-time":"2026-08-09T00:00:00Z","timestamp":1786233600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background\/Objectives: Evaluation of renal tumour masses relies on conventional imaging, which cannot reliably characterise the histopathological type, and no validated blood-based diagnostic marker is available for renal cell carcinoma. The cfDNA integrity index, the ratio of long to short circulating cell-free DNA (cfDNA) fragments, may reflect the necrotic origin of tumour-derived DNA and is a candidate qualitative marker of malignancy. This exploratory, single-centre case\u2013control study assessed the preoperative plasma cfDNA integrity index in patients with clear cell renal cell carcinoma (ccRCC). Methods: Plasma concentrations of 90 bp and 222 bp cfDNA fragments were measured by quantitative real-time PCR (qPCR) in 46 patients with histopathologically confirmed ccRCC (before surgery) and 17 healthy volunteers; the two groups were a convenience sample, were not matched, and differed in age and body-mass index. The cfDNA integrity index was defined as the ratio of the 222 bp to the 90 bp fragment concentration. Results: The cfDNA integrity index was higher in patients with ccRCC than in controls (median 0.28 vs. 0.15; p &lt; 0.001, Mann\u2013Whitney test) and rose progressively across healthy, non-metastatic (M0) and metastatic (M1) groups (p &lt; 0.001, Kruskal\u2013Wallis test; M0 vs. M1 p = 0.004). In unadjusted ROC analysis, both the integrity index (AUC 0.83, 95% CI 0.72\u20130.94) and its long 222 bp fragment component (AUC 0.93) discriminated patients with ccRCC from healthy volunteers, and the index separated metastatic from non-metastatic disease with an AUC of 0.79 (95% CI 0.64\u20130.88). The index was higher in high-grade (Fuhrman G3 + G4) tumours (p = 0.04) and in tumours with lymphovascular invasion (p &lt; 0.001), and correlated with primary-tumour diameter. Conclusions: In this exploratory cohort, the preoperative plasma cfDNA integrity index was higher in patients with ccRCC than in healthy volunteers and was associated with several adverse pathological features; these findings require confirmation in larger, matched studies that include benign renal masses before any diagnostic role can be claimed.<\/jats:p>","DOI":"10.3390\/cancers18162557","type":"journal-article","created":{"date-parts":[[2026,8,10]],"date-time":"2026-08-10T01:20:03Z","timestamp":1786324803000},"page":"2557","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Preoperative Plasma Cell-Free DNA Integrity Index in Clear Cell Renal Cell Carcinoma: An Exploratory Case\u2013Control Study"],"prefix":"10.3390","volume":"18","author":[{"given":"Tomasz","family":"Milecki","sequence":"first","affiliation":[{"name":"Department of Urology and Oncological Urology, Poznan University of Medical Sciences, 60-355 Pozna\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan","family":"St\u0119pka","sequence":"additional","affiliation":[{"name":"Department of Urology and Oncological Urology, Poznan University of Medical Sciences, 60-355 Pozna\u0144, Poland"},{"name":"Doctoral School, Poznan University of Medical Sciences, 61-701 Pozna\u0144, Poland"},{"name":"Department of Urology, Ministry of Internal Affairs Hospital, 61-701 Pozna\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joanna","family":"Weso\u0142y","sequence":"additional","affiliation":[{"name":"Laboratory of High Throughput Technologies, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 61-614 Pozna\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wojciech","family":"Cie\u015blikowski","sequence":"additional","affiliation":[{"name":"Department of Urology and Oncological Urology, Poznan University of Medical Sciences, 60-355 Pozna\u0144, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"17009","DOI":"10.1038\/nrdp.2017.9","article-title":"Renal cell carcinoma","volume":"3","author":"Hsieh","year":"2017","journal-title":"Nat. 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