{"entity":{"id":"microenvironment-inflammation-theory","kind":"term","name":"Microenvironment and inflammation: tumours as wounds that do not heal","aka":["microenvironment theory","inflammation theory of cancer","wounds that do not heal","tumour as an overhealing wound","Virchow hypothesis","stromal theory of cancer"],"tldr":"A tumour is not a lump of cancer cells but a tissue: fibroblasts, vessels and immune cells, recruited by the signals a wound uses and never told to stop. Virchow saw white cells in tumours in 1863; Dvorak called tumours 'wounds that do not heal' in 1986. It explains why chronic inflammation causes about a fifth of cancers and why aspirin, HPV and hepatitis vaccines and anti-angiogenic drugs work.","summary":"The claim. Cancer cells cannot make a tumour alone. They recruit and corrupt normal cells (fibroblasts, macrophages, endothelium, nerves) using the programme of wound healing, and chronic inflammation from infection, irritation or autoimmunity supplies growth factors, survival signals, new vessels and mutagenic oxidants that initiate and promote tumours. In the strong form, the microenvironment is where cancer begins; in the mainstream form, it is an enabling characteristic and a full participant.\n\nWho and when. Virchow described leukocytes in tumours in 1863 and proposed that irritation causes cancer. Dvorak's 1986 essay noted that tumour stroma is generated by the same vascular leak, fibrin deposition and fibroblast activation as granulation tissue. Balkwill and Mantovani (2001) and Coussens and Werb (2002) set out the molecular case for inflammation as a cause; Hanahan and Coussens (2012) catalogued the recruited cells as 'accessories to the crime'; Schäfer and Werner (2008) revisited the overhealing wound. Judah Folkman's angiogenesis hypothesis (1971) and Mina Bissell's microenvironment work are part of the same lineage.\n\nEvidence for. Infections and inflammatory conditions cause cancer: Helicobacter pylori and gastric cancer, hepatitis B and C and liver cancer, ulcerative colitis and colorectal cancer, asbestos and mesothelioma, reflux and oesophageal adenocarcinoma. Long-term aspirin reduces colorectal cancer incidence and cancer death in randomised trial follow-up (Rothwell 2011). Tumour stroma has the cell types and signals of a healing wound, and cancer-associated fibroblasts and tumour-associated macrophages promote growth, invasion and immune exclusion. Anti-inflammatory interleukin-1 beta blockade with canakinumab reduced incident lung cancer in the CANTOS cardiovascular trial. Inflammation became an enabling characteristic in the 2011 hallmarks.\n\nEvidence against and limits. Many cancers arise without recognisable inflammation, and inflammation is also how the immune system attacks tumours: an inflamed, T-cell-rich tumour responds best to checkpoint inhibitors. Anti-inflammatory treatment of established cancer has largely failed: canakinumab did not improve survival in the CANOPY lung cancer trials, and matrix metalloproteinase inhibitors failed in the 1990s. The claim that the microenvironment initiates cancer is hard to separate from the mutations that inflammation causes.\n\nPredictions that held or failed. Held: chronic inflammation is a preventable cause of cancer; removing the cause (H. pylori eradication, hepatitis B vaccination, HPV vaccination, treating hepatitis C) prevents cancer; aspirin prevents colorectal cancer; stroma predicts prognosis. Failed: anti-angiogenic therapy as a broad cure (bevacizumab adds months and resistance follows); anti-inflammatory drugs as treatment for established cancer; stroma depletion in pancreatic cancer (hyaluronidase failed in phase 3).\n\nTherapies that came from it. Aspirin and non-steroidal anti-inflammatory chemoprevention, the HPV and hepatitis B vaccines and H. pylori eradication, anti-VEGF antibodies and kinase inhibitors, and the current trials of fibroblast, macrophage and interleukin targeting. The theory feeds the seed and soil hypothesis (the soil is a microenvironment), the immune surveillance theory and the hallmarks, and it carries forward the tissue organisation field theory's evidence in a form the mainstream accepts.\n\nStatus: established for inflammation's role in causing and promoting cancer and for the stroma as a participant; contested as the primary origin of cancer in place of mutation.","asOf":"2026-09-17","wikipedia":"https://en.wikipedia.org/wiki/Tumor_microenvironment","links":[{"label":"Dvorak, Tumors: wounds that do not heal (NEJM 1986)","url":"https://doi.org/10.1056/NEJM198612253152606"},{"label":"Balkwill and Mantovani, Inflammation and cancer: back to Virchow? (Lancet 2001)","url":"https://doi.org/10.1016/S0140-6736(00)04046-0"},{"label":"Coussens and Werb, Inflammation and cancer (Nature 2002)","url":"https://doi.org/10.1038/nature01322"},{"label":"Hanahan and Coussens, Accessories to the crime: functions of cells recruited to the tumor microenvironment (Cancer Cell 2012)","url":"https://doi.org/10.1016/j.ccr.2012.02.022"},{"label":"Schäfer and Werner, Cancer as an overhealing wound: an old hypothesis revisited (Nature Reviews Molecular Cell Biology 2008)","url":"https://doi.org/10.1038/nrm2455"},{"label":"Rothwell et al., Effect of daily aspirin on long-term risk of death due to cancer (Lancet 2011)","url":"https://doi.org/10.1016/S0140-6736(10)62110-1"},{"label":"Ridker et al., Effect of interleukin-1 beta inhibition with canakinumab on incident lung cancer (CANTOS, Lancet 2017)","url":"https://doi.org/10.1016/S0140-6736(17)32247-X"},{"label":"Van Cutsem et al., Randomized phase III trial of pegvorhyaluronidase alfa with nab-paclitaxel plus gemcitabine (HALO 109-301, JCO 2020)","url":"https://doi.org/10.1200/JCO.20.00590"}],"tags":["theory"],"related":["theories-of-cancer","inflammation","tumor-microenvironment","tissue-organisation-field-theory","seed-and-soil-hypothesis","immune-surveillance-immunoediting","hallmarks-synthesis","mechanical-theory-of-cancer","ageing-tissue-field-theory","inflammation-nfkb","tumor-promoting-inflammation","cancer-associated-fibroblasts","caf-activation-desmoplasia","angiogenic-switch","vegf-angiogenesis","oncogenic-viruses","aspirin-cancer-prevention","hpv-vaccine","macrophage","cold-vs-hot"],"cancers":["colorectal","hcc","cervical"],"sections":[],"technologies":["aspirin-cancer-prevention","hpv-vaccine","chemoprevention"],"targets":["vegf","il6","fap"],"drugs":["bevacizumab","aspirin"],"companies":[],"institutions":[],"pathways":["tumor-microenvironment","inflammation-nfkb","caf-activation-desmoplasia","angiogenic-switch","vegf-angiogenesis","oncogenic-viruses","myeloid-suppression-axis"],"terms":[],"trials":["add-aspirin"],"people":["johanna-joyce","judah-folkman"],"bottlenecks":[],"keyPapers":["paper-balkwill-mantovani-inflammation-virchow-lancet-2001","paper-coussens-werb-inflammation-cancer-nature-2002","paper-quail-joyce-microenvironment-metastasis-natmed-2013"],"journals":[],"dependsOn":[],"notes":[],"category":"Cancer biology"},"route":"/terms/microenvironment-inflammation-theory/","neighbours":{"pathway":[{"id":"caf-activation-desmoplasia","kind":"pathway","name":"Fibroblast activation, desmoplasia & matrix stiffness","route":"/pathways/caf-activation-desmoplasia/"},{"id":"inflammation-nfkb","kind":"pathway","name":"Inflammation & NF-κB","route":"/pathways/inflammation-nfkb/"},{"id":"myeloid-suppression-axis","kind":"pathway","name":"Myeloid suppression: TAMs, MDSCs & don't-eat-me signals","route":"/pathways/myeloid-suppression-axis/"},{"id":"oncogenic-viruses","kind":"pathway","name":"Oncogenic viruses","route":"/pathways/oncogenic-viruses/"},{"id":"angiogenic-switch","kind":"pathway","name":"The angiogenic switch & tumour vessels","route":"/pathways/angiogenic-switch/"},{"id":"theories-of-cancer","kind":"pathway","name":"Theories of cancer: how the ideas connect","route":"/pathways/theories-of-cancer/"},{"id":"tumor-microenvironment","kind":"pathway","name":"Tumour microenvironment (TME)","route":"/pathways/tumor-microenvironment/"},{"id":"vegf-angiogenesis","kind":"pathway","name":"VEGF angiogenesis","route":"/pathways/vegf-angiogenesis/"}],"term":[{"id":"ageing-tissue-field-theory","kind":"term","name":"Ageing tissue and clonal fields: cancer as a disease of old tissue","route":"/terms/ageing-tissue-field-theory/"},{"id":"cancer-associated-fibroblasts","kind":"term","name":"Cancer-associated fibroblasts (CAFs)","route":"/terms/cancer-associated-fibroblasts/"},{"id":"tumor-promoting-inflammation","kind":"term","name":"Enabling characteristic: tumour-promoting inflammation","route":"/terms/tumor-promoting-inflammation/"},{"id":"hallmarks-synthesis","kind":"term","name":"Hallmarks of cancer as a synthesis of the theories","route":"/terms/hallmarks-synthesis/"},{"id":"cold-vs-hot","kind":"term","name":"Hot vs cold tumours","route":"/terms/cold-vs-hot/"},{"id":"immune-surveillance-immunoediting","kind":"term","name":"Immune surveillance and cancer immunoediting","route":"/terms/immune-surveillance-immunoediting/"},{"id":"inflammation","kind":"term","name":"Inflammation","route":"/terms/inflammation/"},{"id":"macrophage","kind":"term","name":"Macrophage","route":"/terms/macrophage/"},{"id":"mechanical-theory-of-cancer","kind":"term","name":"Mechanical theory: stiffness, pressure and force as causes","route":"/terms/mechanical-theory-of-cancer/"},{"id":"seed-and-soil-hypothesis","kind":"term","name":"Seed and soil hypothesis of metastasis (Paget)","route":"/terms/seed-and-soil-hypothesis/"},{"id":"tissue-organisation-field-theory","kind":"term","name":"Tissue organisation field theory (Sonnenschein and Soto)","route":"/terms/tissue-organisation-field-theory/"}],"technology":[{"id":"aspirin-cancer-prevention","kind":"technology","name":"Aspirin for cancer prevention and adjuvant therapy","route":"/technologies/aspirin-cancer-prevention/"},{"id":"chemoprevention","kind":"technology","name":"Chemoprevention & risk-reducing surgery","route":"/technologies/chemoprevention/"},{"id":"hpv-vaccine","kind":"technology","name":"HPV & HBV vaccination","route":"/technologies/hpv-vaccine/"}],"cancer":[{"id":"cervical","kind":"cancer","name":"Cervical cancer","route":"/cancers/cervical/"},{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"},{"id":"hcc","kind":"cancer","name":"Hepatocellular carcinoma","route":"/cancers/hcc/"}],"target":[{"id":"fap","kind":"target","name":"FAP","route":"/targets/fap/"},{"id":"il6","kind":"target","name":"Interleukin-6 and IL-6 receptor","route":"/targets/il6/"},{"id":"vegf","kind":"target","name":"VEGF / VEGFR","route":"/targets/vegf/"}],"drug":[{"id":"aspirin","kind":"drug","name":"Aspirin","route":"/drugs/aspirin/"},{"id":"bevacizumab","kind":"drug","name":"Bevacizumab","route":"/drugs/bevacizumab/"}],"trial":[{"id":"add-aspirin","kind":"trial","name":"Add-Aspirin","route":"/trials/add-aspirin/"}],"person":[{"id":"johanna-joyce","kind":"person","name":"Johanna Joyce","route":"/people/johanna-joyce/"},{"id":"judah-folkman","kind":"person","name":"Judah Folkman","route":"/people/judah-folkman/"}],"paper":[{"id":"paper-balkwill-mantovani-inflammation-virchow-lancet-2001","kind":"paper","name":"Balkwill and Mantovani 2001: inflammation and cancer, back to Virchow?","route":"/key-papers/paper-balkwill-mantovani-inflammation-virchow-lancet-2001/"},{"id":"paper-coussens-werb-inflammation-cancer-nature-2002","kind":"paper","name":"Coussens and Werb 2002: inflammation and 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