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An exploratory pilot study applied multivariate analysis and principal component analysis–discriminant analysis to LC/MS proteomic results from lung cancer patients, a gastric cancer patient, and a healthy control. Protein signal patterns differed by cohort.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/identifying-the-primary-tumor-site-and-distinguishing-false-positives-in-patients-with-elevated-serum-carcinoembryonic-antigen/368610/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/identifying-the-primary-tumor-site-and-distinguishing-false-positives-in-patients-with-elevated-serum-carcinoembryonic-antigen/368610.png","ImageObject",300,407,{"name":92,"@type":93},"Putri","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-28","2026-09-23",true,{"@type":102,"interactionType":103,"userInteractionCount":29},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"Why is identifying a primary tumor site difficult when serum CEA is elevated?","Question",{"text":112,"@type":113},"CEA is measured as a value, but no established method indicates whether the elevation reflects a false positive or a specific primary cancer site. As a result, clinicians often need expensive and invasive investigations to locate the lesion.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"What analytical approach was used to distinguish tumor origins and false positives?",{"text":117,"@type":113},"The study used principal component analysis–discriminant analysis (PCA-DA) on proteomic results obtained with liquid chromatography–mass spectrometry (LC/MS). It compared LC/MS protein signal patterns across patients and a healthy control.",{"name":119,"@type":110,"acceptedAnswer":120},"What did the study find regarding protein differences between lung and gastric cancers?",{"text":121,"@type":113},"No differences in specific proteins associated with high CEA levels were detected between lung and gastric cancers using LC/MS. However, statistical analysis showed cohort-specific separation in the four-quadrant matrix scatter plot.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},368610,1790464294,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":29,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":29,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":143,"read_time":144},962085571259,"https://ap-avatar.wpscdn.com/davatar_29158cc5080c5b710cf443261637dec0","doi: 10.21873/invivo.14035  \nIdentifying the Primary Tumor Site and Distinguishing False‐positives in Patients  \nWith Elevated Serum Carcinoembryonic Antigen  \nHIROAKI SATOH1, TAKUMI SAKAMOTO2, YUTAKA TAKAHASHI3, KUNIHIKO MIYAZAKI4 and SATOSHI INAGAWA5  \n1 Division of Respiratory Medicine, Mito Medical Center, University of Tsukuba‐Mito Kyodo General Hospital, Mito, Japan; 2 Department of Cellular and Molecular Anatomy, Hamamatsu University School of Medicine, Hamamatsu, Japan;  \n3 Preppers Corporation, Venture company originating from Hamamatsu University School of Medicine, Hamamatsu, Japan;  \n4 Division of Respiratory Medicine, Ryugasaki Saiseikai General Hospital, Ryugasaki, Japan; 5 Division of Surgery, Takahagi Kyodo Hospital, Takahagi, Japan  \nAbstract  \nBackground/Aim: Carcinoembryonic antigen (CEA) is a tumor marker that is frequently evaluated clinically for gastrointestinal and lung cancers. CEA is a glycoprotein antigen, and only the “value” measured by enzyme‑linked immunosorbent assay is provided in the clinical setting. At present, no method has been established to indicate whether the value is a false‑positive elevation or whether there is a primary cancer site. To obtain clues on how to identify the originating site in patients with cancer with high CEA levels and to identify CEA false‑positives in healthy individuals, we conducted an exploratory study.  \nPatients and Methods: A pilot study was performed using the multivariate analysis method and principal component analysis‑discriminant analysis on proteomic results obtained using liquid chromatography‑mass spectrometry (LC/MS) in two patients with lung cancer, one patient with gastric cancer, and one healthy control individual. Results: No differences in specific proteins associated with high CEA levels were detected between lung and gastric cancers using LC/MS. Therefore, we performed statistical analysis using principal component analysis‑discriminant analysis to determine whether there were differences in the protein signal patterns obtained using LC/MS. The results showed that the plots obtained for each patient and the healthy control were located in different quadrants of the four‑quadrant matrix scatter plot.  \nConclusion: Our results suggest the possibility of visually differentiating the primary tumor site in patients with elevated CEA levels. This method may also help recognize false‑positive CEA results.  \nKeywords: Tumor marker, carcinoembryonic antigen, CEA, differential diagnosis.  \n✉  \nHiroaki Satoh, MD, Ph.D., Division of Respiratory Medicine, Mito Medical Center, University of Tsukuba, 3‑2‑7 Miya‑machi,  \nMito, Ibaraki, 3100015, Japan. E‑[mail: hirosato@md.tsukuba.ac.jp](mail: hirosato@md.tsukuba.ac.jp)  \nReceived March 10, 2025 | Revised April 4, 2025 | Accepted April 7, 2025  \nThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.  \n©2025 The Author(s) . Anticancer Research is published by the International Institute of Anticancer Research.  \nIntroduction  \nCarcinoembryonic antigen (CEA) is a tumor marker that has been used for decades to assess the prognosis and follow‑ up of patients with adenocarcinomas (1‑12), including gastrointestinal and lung cancers (1, 2, 6‑12). In some countries, CEA is also measured during cancer screening and early diagnosis (1, 6‑9). CEA is a glycoprotein antigen (13), and only the “value” measured by enzyme‑linked immunosorbent assay is provided in the clinical setting, and at present no method has been established to indicate whether the value is a false‑positive elevation or whether there is a primary cancer site (14). When elevated serum CEA levels on screening are found in asymptomatic individuals, expensive and invasive multi‑organ testing, such as positron emission tomography and endoscopy, is required to detect the primary lesion (13). In addition, it has be","cbCaicwYw5zpQDcB","https://ap.wps.com/l/cbCaicwYw5zpQDcB","pdf",1937533,"English","# Abstract\n## Background/Aim\n## Patients and Methods\n## Conclusion\n# Introduction\n# Patients and Methods","[{\"question\":\"Why is identifying a primary tumor site difficult when serum CEA is elevated?\",\"answer\":\"CEA is measured as a value, but no established method indicates whether the elevation reflects a false positive or a specific primary cancer site. As a result, clinicians often need expensive and invasive investigations to locate the lesion.\"},{\"question\":\"What analytical approach was used to distinguish tumor origins and false positives?\",\"answer\":\"The study used principal component analysis–discriminant analysis (PCA-DA) on proteomic results obtained with liquid chromatography–mass spectrometry (LC/MS). It compared LC/MS protein signal patterns across patients and a healthy control.\"},{\"question\":\"What did the study find regarding protein differences between lung and gastric cancers?\",\"answer\":\"No differences in specific proteins associated with high CEA levels were detected between lung and gastric cancers using LC/MS. However, statistical analysis showed cohort-specific separation in the four-quadrant matrix scatter plot.\"}]","Identifying the Primary Tumor Site and Distinguishing False-positives in Patients With Elevated Serum Carcinoembryonic Antigen | PDF",1790177719,15]