{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T05:07:52Z","timestamp":1789967272160,"version":"4.0.1"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T00:00:00Z","timestamp":1789948800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>In the era of immune checkpoint inhibitor\u2013tyrosine kinase inhibitor (ICI\u2013TKI) combination therapy for metastatic renal cell carcinoma (mRCC), reliable biomarkers for prognostic stratification and long-term prognosis remain clinically unmet needs. This study aimed to investigate the prognostic significance of baseline serum IgG in patients with mRCC receiving first-line systemic therapy and to evaluate its potential in complementing current risk stratification models.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We retrospectively analyzed 153 patients with mRCC receiving first-line ICI-TKI therapy between May 2019 and April 2026. Baseline serum IgG levels were categorized as elevated (&amp;gt;17.4 g\/L) or normal based on the institutional reference limit. Survival outcomes were assessed using Kaplan\u2013Meier analysis and Cox proportional hazards models. A prognostic nomogram was developed for individualized survival prediction.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The median follow-up was 29.0 months. Elevated baseline IgG was associated with higher IMDC risk (P\u00a0=\u00a00.022). Kaplan\u2013Meier analysis showed significantly worse overall survival (OS; P &amp;lt; 0.001) and progression-free survival (PFS; P\u00a0=\u00a00.049) in patients with elevated IgG. In multivariable analysis, elevated IgG was not associated with PFS but remained an independent predictor of inferior OS (HR\u00a0=\u00a02.55; 95% CI, 1.30\u20135.00; P\u00a0=\u00a00.006). Incorporating IgG into the IMDC model improved the C-index from 0.645 to 0.689, with the greatest incremental benefit observed for 3-year OS prediction. The exploratory nomogram demonstrated acceptable calibration, particularly for 3-year OS prediction.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Baseline serum IgG is an independent prognostic biomarker for OS in mRCC patients treated with first-line ICI\u2013TKI therapy. Its integration into the IMDC model improves survival prediction and provides additional prognostic information in the immunotherapy era.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fonc.2026.1928984","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T04:28:08Z","timestamp":1789964888000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Prognostic performance of baseline serum immunoglobulin G in patients with metastatic renal cell carcinoma receiving first-line ICI\u2013TKI therapy"],"prefix":"10.3389","volume":"16","author":[{"given":"Hongwei","family":"Wang","sequence":"first","affiliation":[{"name":"Department of Urology, National Cancer Center\/National Clinical Research Center for Cancer\/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College","place":["Beijing, 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Medical Sciences and Peking Union Medical College","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianzhong","family":"Shou","sequence":"additional","affiliation":[{"name":"Department of Urology, National Cancer Center\/National Clinical Research Center for Cancer\/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongzhe","family":"Shi","sequence":"additional","affiliation":[{"name":"Department of Urology, National Cancer Center\/National Clinical Research Center for Cancer\/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,21]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.3322\/caac.21834","article-title":"Global cancer 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