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To translate these findings to animals, researchers tested canine malignancies and distinguished analogous Gram-positive agents from conventional bacteria using Gram staining across diverse tumor types.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/healthcare/","Healthcare",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/beyond-bacteria-large-agents-with-analogies-to-mimiviruses-detected-in-canine-cancers-reexamining-gram-staining-in-cancer-diagnostics/353817/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/beyond-bacteria-large-agents-with-analogies-to-mimiviruses-detected-in-canine-cancers-reexamining-gram-staining-in-cancer-diagnostics/353817.png","ImageObject",300,407,{"name":42,"@type":43},"Aurelia","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-31","2026-09-22",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",14,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"Why is Gram staining considered in this research on cancer diagnostics?","Question",{"text":63,"@type":64},"Gram staining is used to classify bacteria by cell-wall properties, but the study focuses on large agents that can also retain Gram-staining signals, challenging the assumption that Gram-positive staining indicates only bacteria.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"What did the researchers look for in canine tumors?",{"text":68,"@type":64},"They evaluated canine malignancies for analogous Gram-positive agents that resemble Mimivirus-related findings in human tissues, and they differentiated these agents from traditional bacteria.",{"name":70,"@type":61,"acceptedAnswer":71},"How were the canine tumor samples organized in the study?",{"text":72,"@type":64},"Gram staining was applied to 35 canine tumors across multiple malignancy types, including sarcomas, carcinomas, and round cell tumors; 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Front. Vet. Sci. 13:1759298 .  \ndoi: 10.3389/fvets.2026.1759298  \nCOPYRIGHT  \n© 2026 Lusi, Caicci, Zappone, Quartuccio, Dragà, Ieni, Mannarino, Mazzullo and Rifici. This is an  \nopen-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.  \nBeyond bacteria: large agents with analogies to Mimiviruses detected in canine cancers:  \nreexamining Gram staining in cancer diagnostics  \nElena Angela Lusi 1*, Federico Caicci 2, Viola Zappone3*, Marco Quartuccio3, Ilaria Dragà3, Antonio Ieni4,  \nCornelia Mannarino3, Giuseppe Mazzullo3 and Claudia Rifici3  \n1St Vincent Health Care Group-UCD, Dublin, Ireland, 2Department of Biology, Electron Microscopy Unit, University of Padua, Padua, Italy, 3Department of Veterinary Sciences, University of Messina, Messina, Italy, 4Department of Human Pathology in Adult and Developmental Age \"Gaetano Barresi\", Section of Pathology, University of Messina, Messina, Italy  \nWhile Gram staining is traditionally used for classifying bacteria based on their cell wall properties, Mimiviruses and large mammalian agents can also retain the Gram stain, despite not being typical bacteria. In fact, Mimivirus-like agents that exhibit Gram-positive staining were first found in human tissues, particularly in malignant samples, suggesting that these agents may be involved in a unique carcinogenic process. In order to translate the findings published in human medicine to animal models, we evaluated for the first time the presence of analogous Gram-positive agents in canine malignancies and differentiate them from traditional bacteria. Using Gram staining, we analyzed 35 canine tumors across various malignancy types, including 7 sarcomas, 15 carcinomas, and 13 round cell tumors such as mast cell tumors, transmissible venereal tumors and melanomas. Normal tissues and bacteria were used as controls. We were able to identify Gram-positive granulations, exhibiting intracytoplasmic, intra-nuclear and perinuclear patterns, measuring 1–2 μm that were distinct from traditional bacteria. This study, the first of its kind in the veterinary literature, supports comparable published findings in human research and advances our knowledge of the pathophysiology of cancer across species.  \nKEYWORDS  \ncanine cancer, Gram staining, human cancer, Mimivirus-like agent, oncogenic agent  \n1 Introduction  \nThe discovery of Mimiviruses, large DNA viruses that infect amoebas, challenged traditional distinctions between viruses and cellular organisms and prompted significant reevaluation in microbiology and virology. In particular, their discovery has challenged existing paradigms regarding the complexity and classification of viruses, introduced the concept that virus","cbCailxAPIVFs5Pm","https://ap.wps.com/l/cbCailxAPIVFs5Pm","pdf",3011226,"English","# Key points\n## Background and rationale\n## Study design and sampling\n## Gram-staining findings and differentiation\n## Implications across species\n# Introduction\n## Mimiviruses and revised classifications\n## Large mammalian agents in human cancers\n## Need for veterinary/animal validation\n# Materials and methods\n## Specimens and tumor categories","[{\"question\":\"Why is Gram staining considered in this research on cancer diagnostics?\",\"answer\":\"Gram staining is used to classify bacteria by cell-wall properties, but the study focuses on large agents that can also retain Gram-staining signals, challenging the assumption that Gram-positive staining indicates only bacteria.\"},{\"question\":\"What did the researchers look for in canine tumors?\",\"answer\":\"They evaluated canine malignancies for analogous Gram-positive agents that resemble Mimivirus-related findings in human tissues, and they differentiated these agents from traditional bacteria.\"},{\"question\":\"How were the canine tumor samples organized in the study?\",\"answer\":\"Gram staining was applied to 35 canine tumors across multiple malignancy types, including sarcomas, carcinomas, and round cell tumors; normal tissues and bacteria were used as controls.\"}]","Beyond bacteria - large agents with analogies to Mimiviruses detected in canine cancers - reexamining Gram staining in cancer diagnostics | PDF",1790107400,18]