{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T02:55:04Z","timestamp":1785293704435,"version":"3.55.0"},"reference-count":24,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,4,10]],"date-time":"2025-04-10T00:00:00Z","timestamp":1744243200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Research Foundation of Korea (NRF)","award":["2021R1G1A1010833"],"award-info":[{"award-number":["2021R1G1A1010833"]}]},{"name":"National Research Foundation of Korea (NRF)","award":["2021R1G1A1007886"],"award-info":[{"award-number":["2021R1G1A1007886"]}]},{"name":"National Research Foundation of Korea (NRF)","award":["2025-0013"],"award-info":[{"award-number":["2025-0013"]}]},{"name":"Soonchunhyang University Research Fund","award":["2021R1G1A1010833"],"award-info":[{"award-number":["2021R1G1A1010833"]}]},{"name":"Soonchunhyang University Research Fund","award":["2021R1G1A1007886"],"award-info":[{"award-number":["2021R1G1A1007886"]}]},{"name":"Soonchunhyang University Research Fund","award":["2025-0013"],"award-info":[{"award-number":["2025-0013"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background\/Objectives: Malignant ascites frequently arises in advanced cancers with peritoneal metastasis and is associated with poor outcomes. Known mechanisms include lymphatic obstruction by tumor cells, increased vascular permeability, and sodium retention via the renin\u2013angiotensin\u2013aldosterone system; however, the pathogenesis remains not fully understood. We investigated whether gut and bladder microbiomes correlate with malignant ascites development or progression and whether the immune microenvironment in ascitic fluid is altered. Methods: We enrolled 66 histologically confirmed cancer patients, dividing them into malignant ascites (n = 20) and non-ascites (n = 46) groups. Stool, urine, and ascitic fluid samples were analyzed using 16S rRNA next-generation sequencing. Immune cell subsets in ascitic fluid were characterized using flow cytometry. Results: In 19 of the 20 malignant ascites samples, the bacterial load was too low for reliable 16S rRNA sequencing, suggesting that malignant ascites is largely sterile. The overall gut microbiome diversity did not differ significantly by ascites status, although a trend emerged in patients with peritoneal metastasis, including the enrichment of class Clostridia and Gammaproteobacteria. Bladder microbiome analysis also showed no significant differences in ascites or metastasis status. Flow cytometry revealed reduced T-cell (CD3+, CD4+, CD8+) and NK cell (CD56+) populations compared to data from cirrhotic ascites. Conclusions: Malignant ascites exhibit minimal bacterial biomass, making comprehensive microbiome analysis challenging. Although no major global changes were noted in gut and bladder microbiomes, specific taxa were linked to peritoneal metastasis. These findings highlight an immunosuppressive ascitic environment and suggest that larger-scale or multi-omics approaches may help elucidate the role of microbiota in malignant ascites.<\/jats:p>","DOI":"10.3390\/cancers17081280","type":"journal-article","created":{"date-parts":[[2025,4,10]],"date-time":"2025-04-10T07:41:51Z","timestamp":1744270911000},"page":"1280","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Microbial and Immune Landscape of Malignant Ascites: Insights from Gut, Bladder, and Ascitic Fluid Analyses"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5897-8309","authenticated-orcid":false,"given":"Jina","family":"Yun","sequence":"first","affiliation":[{"name":"Division of Hematology-Oncology, Department of Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ju-Sun","family":"Song","sequence":"additional","affiliation":[{"name":"GC Genome, Department of Laboratory Medicine, Green Cross Laboratories, Seoul 16924, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7802-0381","authenticated-orcid":false,"given":"Jeong-Ju","family":"Yoo","sequence":"additional","affiliation":[{"name":"Division of Hepatology, Department of Medicine, Soonchunhyang University Bucheon Hospital, Bucheon 14584, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8021-9605","authenticated-orcid":false,"given":"Solbi","family":"Kweon","sequence":"additional","affiliation":[{"name":"GC Genome, Department of Laboratory Medicine, Green Cross Laboratories, Seoul 16924, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoon-Young","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Surgery, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daero","family":"Lim","sequence":"additional","affiliation":[{"name":"Department of Surgery, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jung-Cheol","family":"Kuk","sequence":"additional","affiliation":[{"name":"Department of Surgery, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hyun-Jung","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Hematology-Oncology, Department of Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seong-Kyu","family":"Park","sequence":"additional","affiliation":[{"name":"Division of Hematology-Oncology, Department of Medicine, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,4,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1104","DOI":"10.1002\/hep.1840080521","article-title":"Ascitic fluid analysis in malignancy-related ascites","volume":"8","author":"Runyon","year":"1988","journal-title":"Hepatology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1016\/j.ejca.2005.11.018","article-title":"Malignant ascites: Systematic review and guideline for treatment","volume":"42","author":"Becker","year":"2006","journal-title":"Eur. J. Cancer"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"999","DOI":"10.1016\/j.jamcollsurg.2004.01.035","article-title":"Malignant ascites: Past, present, and future","volume":"198","author":"Adam","year":"2004","journal-title":"J. Am. Coll. Surg."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"527","DOI":"10.1038\/nrgastro.2017.72","article-title":"The gut microbiome and liver cancer: Mechanisms and clinical translation","volume":"14","author":"Yu","year":"2017","journal-title":"Nat. Rev. Gastroenterol. Hepatol."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Cheng, H., Wang, Z., Cui, L., Wen, Y., Chen, X., Gong, F., and Yi, H. (2020). Opportunities and Challenges of the Human Microbiome in Ovarian Cancer. Front. Oncol., 10.","DOI":"10.3389\/fonc.2020.00163"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"103856","DOI":"10.1016\/j.critrevonc.2022.103856","article-title":"The intestinal microbiota in colorectal cancer metastasis\u2014Passive observer or key player?","volume":"180","author":"Patel","year":"2022","journal-title":"Crit. Rev. Oncol."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Colella, M., Topi, S., Palmirotta, R., D\u2019agostino, D., Charitos, I.A., Lovero, R., and Santacroce, L. (2023). An Overview of the Microbiota of the Human Urinary Tract in Health and Disease: Current Issues and Perspectives. Life, 13.","DOI":"10.3390\/life13071486"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"2069","DOI":"10.1245\/s10434-023-14553-6","article-title":"Characterizing the Immune Environment in Peritoneal Carcinomatosis: Insights for Novel Immunotherapy Strategies","volume":"31","author":"Wagner","year":"2023","journal-title":"Ann. Surg. Oncol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Yang, C.J., Song, J.S., Yoo, J.-J., Park, K.W., Yun, J., Kim, S.G., and Kim, Y.S. (2024). 16S rRNA Next-Generation Sequencing May Not Be Useful for Examining Suspected Cases of Spontaneous Bacterial Peritonitis. Medicina, 60.","DOI":"10.3390\/medicina60020289"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Yoo, J.-J., Song, J.S., Bin Kim, W., Yun, J., Shin, H.B., Jang, M.-A., Ryu, C.B., Kim, S.S., Chung, J.C., and Kuk, J.C. (2022). Gardnerella vaginalis in Recurrent Urinary Tract Infection Is Associated with Dysbiosis of the Bladder Microbiome. J. Clin. Med., 11.","DOI":"10.3390\/jcm11092295"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"852","DOI":"10.1038\/s41587-019-0209-9","article-title":"Reproducible, Interactive, Scalable and Extensible Microbiome Data Science using QIIME 2","volume":"37","author":"Bolyen","year":"2019","journal-title":"Nat. Biotechnol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1038\/nmeth.3869","article-title":"DADA2: High-resolution sample inference from Illumina amplicon data","volume":"13","author":"Callahan","year":"2016","journal-title":"Nat. Methods"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Bokulich, N.A., Kaehler, B.D., Rideout, J.R., Dillon, M., Bolyen, E., Knight, R., Huttley, G.A., and Gregory Caporaso, J. (2018). Optimizing taxonomic classification of marker-gene amplicon sequences with QIIME 2\u2019s q2-feature-classifier plugin. Microbiome, 6.","DOI":"10.1186\/s40168-018-0470-z"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Segata, N., Izard, J., Waldron, L., Gevers, D., Miropolsky, L., Garrett, W.S., and Huttenhower, C. (2011). Metagenomic biomarker discovery and explanation. Genome Biol., 12.","DOI":"10.1186\/gb-2011-12-6-r60"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1111\/j.2041-210X.2011.00127.x","article-title":"Distance-based multivariate analyses confound location and dispersion effects","volume":"3","author":"Warton","year":"2012","journal-title":"Methods Ecol. Evol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"111828","DOI":"10.1016\/j.nut.2022.111828","article-title":"Role of lactobacillus strains in the management of colorectal cancer: An overview of recent advances","volume":"103\u2013104","author":"Ghorbani","year":"2022","journal-title":"Nutrition"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Chen, L., Li, Z., Zeng, T., Zhang, Y.-H., Liu, D., Li, H., Huang, T., and Cai, Y.-D. (2020). Identifying Robust Microbiota Signatures and Interpretable Rules to Distinguish Cancer Subtypes. Front. Mol. Biosci., 7.","DOI":"10.3389\/fmolb.2020.604794"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1156","DOI":"10.1126\/science.aah5043","article-title":"Potential role of intratumor bacteria in mediating tumor resistance to the chemotherapeutic drug gemcitabine","volume":"357","author":"Geller","year":"2017","journal-title":"Science"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1007\/s12672-024-01313-5","article-title":"Short-chain fatty acids play a positive role in colorectal cancer","volume":"15","author":"Liu","year":"2024","journal-title":"Discov. Oncol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"S471","DOI":"10.1093\/cid\/ciad640","article-title":"The Role of the Gut Microbiome in Cancer: A Review, With Special Focus on Colorectal Neoplasia and Clostridioides difficile","volume":"77","author":"Anderson","year":"2023","journal-title":"Clin. Infect. Dis."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1111\/j.1440-1746.2006.04229.x","article-title":"Lymphocyte subsets and cytokines in ascitic fluid of decompensated cirrhotic patients with and without spontaneous ascites infection","volume":"21","author":"Kiyici","year":"2006","journal-title":"J. Gastroenterol. Hepatol."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Almeida-Nunes, D.L., Mendes-Frias, A., Silvestre, R., Dinis-Oliveira, R.J., and Ricardo, S. (2022). Immune Tumor Microenvironment in Ovarian Cancer Ascites. Int. J. Mol. Sci., 23.","DOI":"10.3390\/ijms231810692"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Rickard, B.P., Conrad, C., Sorrin, A.J., Ruhi, M.K., Reader, J.C., Huang, S.A., Franco, W., Scarcelli, G., Polacheck, W.J., and Roque, D.M. (2021). Malignant Ascites in Ovarian Cancer: Cellular, Acellular, and Biophysical Determinants of Molecular Characteristics and Therapy Response. Cancers, 13.","DOI":"10.3390\/cancers13174318"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"100645","DOI":"10.1016\/j.xkme.2023.100645","article-title":"The Gut-Peritoneum Axis in Peritoneal Dialysis and Peritoneal Fibrosis","volume":"5","author":"Stepanova","year":"2023","journal-title":"Kidney Med."}],"container-title":["Cancers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6694\/17\/8\/1280\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:12:06Z","timestamp":1760029926000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6694\/17\/8\/1280"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,10]]},"references-count":24,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2025,4]]}},"alternative-id":["cancers17081280"],"URL":"https:\/\/doi.org\/10.3390\/cancers17081280","relation":{},"ISSN":["2072-6694"],"issn-type":[{"value":"2072-6694","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,4,10]]}}}