OnCo

Cold tumours: deserts and exclusion

Three immune weathers: inflamed (T cells inside), excluded (stuck at the edge), desert (none). Most common cancers are cold. Radiation, viruses, STING agonists and vessel-opening drugs try to warm them; engagers and CAR-T bring their own T cells.

Diagram

Pick a product above a diagram to see the nodes it hits and the escape routes below the block. Hover or tap any node or arrow for what it is; every node opens its target, glossary entry or the pathway page. Violet boxes are druggable targets.

Light up a product:+59 more via the Connected tab
Low TMB, MHC loss activates Immune desertβ-catenin, PTEN loss → no cDC1 activates Immune desertCXCL9/10 silenced (EZH2) activates Immune desertTGF-β CAFs, collagen activates Immune exclusionAbnormal vessels (VEGF) activates Immune exclusionMyeloid barrier activates Immune exclusionImmune desert inhibits Inflamed → PD-1 responseImmune exclusion inhibits Inflamed → PD-1 responseRT, STING, viruses, vaccines activates Inflamed → PD-1 responseRT, STING, viruses, vaccines inhibits Immune desertLow TMB, MHC lossLow TMB, MHC lossβ-catenin, PTEN loss → no cDC1: PIK3CA is the most commonly mutated gene in hormone-driven breast cancer. Drugs against it work, but hitting it cleanly without raising blood sugar took years.β-catenin, PTEN loss → no…CXCL9/10 silenced (EZH2): EZH2 is an enzyme that silences genes. The first drug against it treated a rare sarcoma and some lymphomas until it was withdrawn in 2026 for causing second blood cancers.CXCL9/10 silenced (EZH2)Immune desertImmune desertTGF-β CAFs, collagen: FAP (fibroblast activation protein) sits on the cancer-associated fibroblasts that scaffold more than 90% of epithelial cancers and is almost absent from normal adult tissue.TGF-β CAFs, collagenAbnormal vessels (VEGF): The signal tumours use to grow their own blood supply. Blocking it starves tumours and, surprisingly, helps immunotherapy work.Abnormal vessels (VEGF)Immune exclusionImmune exclusionInflamed → PD-1 response: PD-1 is a brake on T cells. Blocking it releases the immune system against the tumour and has cured some previously incurable cancers.Inflamed → PD-1 responseRT, STING, viruses, vaccinesRT, STING, viruses, vacci…Myeloid barrier: The receptor that macrophages depend on; blocking it shrinks tenosynovial giant cell tumour (a CSF1-driven tumour) and depletes tumour-supporting macrophages, though the latter has not yet helped patients with common…Myeloid barrieractivatesinhibitsdruggable target (click)hit by selected productescape route
Cold tumours: immune deserts and exclusionTumours come in three immune weathers: inflamed (T cells inside, checkpoint drugs work), excluded (T cells stuck at the edge), and desert (no T cells at all). Most common cancers are excluded or desert, and turning them 'hot' is the central problem of immunotherapy.

Three kinds of town: one where the police already patrol the streets (inflamed), one where they mill about outside a wall (excluded), and one with no police station at all (desert). Removing the officers' handcuffs (PD-1 blockade) only helps in the first; the second needs a gate, the third needs recruitment.

Radiation, chemo, ADC payload activates Cytosolic dsDNA / micronucleiCytosolic dsDNA / micronuclei activates cGAScGAS activates cGAMPENPP1 inhibits cGAMPcGAMP activates STINGSTING activates TBK1 → IRF3 / NF-κBTBK1 → IRF3 / NF-κB activates Type I IFN, CXCL10 → T-cell recruitmentRadiation, chemo, ADC payloadRadiation, chemo, ADC pay…Cytosolic dsDNA / micronucleiCytosolic dsDNA / micronu…cGAScGAScGAMPcGAMPENPP1ENPP1STINGSTINGTBK1 → IRF3 / NF-κB: TBK1 (Serine/threonine-protein kinase TBK1) is a protein kinase, an enzyme that switches other proteins on by adding phosphate groups.TBK1 → IRF3 / NF-κBType I IFN, CXCL10 → T-cell recruitmentType I IFN, CXCL10 → T-ce…activatesinhibitsdruggable target (click)hit by selected productescape route
cGAS-STING innate sensingcGAS-STING is the cell's alarm for DNA in the wrong place. Radiation, chemotherapy, and ADCs spill DNA into the cytoplasm; cGAS detects it, STING sounds the alarm, and interferon calls in the immune system.

A smoke detector wired to the fire brigade. DNA in the cytoplasm is smoke; cGAS is the detector; STING is the alarm bell; interferon is the 999 call that brings the immune system. Many tumours have quietly removed the batteries.

Latent TGF-β (activated by integrins) activates TGFBR2 / ALK5TGFBR2 / ALK5 activates SMAD2/3-SMAD4SMAD2/3-SMAD4 activates Cytostasis (early)SMAD2/3-SMAD4 activates EMT, CAF activationSMAD2/3-SMAD4 activates T-cell exclusionSMAD4 loss (PDAC) inhibits SMAD2/3-SMAD4Latent TGF-β (activated by integrins)Latent TGF-β (activated b…TGFBR2 / ALK5TGFBR2 / ALK5SMAD2/3-SMAD4SMAD2/3-SMAD4Cytostasis (early)Cytostasis (early)EMT, CAF activationEMT, CAF activationT-cell exclusionT-cell exclusionSMAD4 loss (PDAC): SMAD4 (SMAD family member 4) is a protein that switches other genes on and off. The public catalogues list it as a drug target, an oncogene driver, a tumour suppressor and a biomarker, and clinical evidence ties its…SMAD4 loss (PDAC)activatesinhibitsdruggable target (click)hit by selected productescape route
TGF-β signallingA signal that stops normal cells from dividing but, once a cancer is established, switches sides: it builds scar-like stroma, walls out immune cells, and pushes cells into a migratory state.

A town planner who first refuses all new building (tumour suppressor) and then, corrupted, builds walls and moats around the tumour that keep the police out (immune exclusion).

Also drawn for this stageWnt / β-catenin

What happens

In plain words, then the glossary entries the stage rests on. Chapter 6, Escaping the immune system: Every tumour that exists has already beaten the immune system once.

Three immune weathers: inflamed (T cells inside), excluded (stuck at the edge), desert (none). Most common cancers are cold. Radiation, viruses, STING agonists and vessel-opening drugs try to warm them; engagers and CAR-T bring their own T cells.

Cold tumours: immune deserts and exclusion. Tumours come in three immune weathers: inflamed (T cells inside, checkpoint drugs work), excluded (T cells stuck at the edge), and desert (no T cells at all). Most common cancers are excluded or desert, and turning them 'hot' is the central problem of immunotherapy.

cGAS-STING innate sensing. cGAS-STING is the cell's alarm for DNA in the wrong place. Radiation, chemotherapy, and ADCs spill DNA into the cytoplasm; cGAS detects it, STING sounds the alarm, and interferon calls in the immune system.

TGF-β signalling. A signal that stops normal cells from dividing but, once a cancer is established, switches sides: it builds scar-like stroma, walls out immune cells, and pushes cells into a migratory state.

Wnt / β-catenin. Wnt/β-catenin is a developmental pathway hijacked by colorectal cancer. Normally a destruction complex keeps β-catenin low; losing APC lets it flood the nucleus and drive growth genes.

The molecular players

The proteins and genes at this stage, with their role and how many products act on each. Listed players come from the atlas; drawn players sit as nodes in the diagrams above.

  • The signal tumours use to grow their own blood supply. Blocking it starves tumours and, surprisingly, helps immunotherapy work.

  • EZH2 is an enzyme that silences genes. The first drug against it treated a rare sarcoma and some lymphomas until it was withdrawn in 2026 for causing second blood cancers.

  • FAP (fibroblast activation protein) sits on the cancer-associated fibroblasts that scaffold more than 90% of epithelial cancers and is almost absent from normal adult tissue. FAPI PET tracers therefore light up tumours with high contrast, including pancreatic, gastric and low-grade cancers where FDG PET is weak, and FAP-targeted radioligands are in development.

  • PD-1 is a brake on T cells. Blocking it releases the immune system against the tumour and has cured some previously incurable cancers.

  • PIK3CA is the most commonly mutated gene in hormone-driven breast cancer. Drugs against it work, but hitting it cleanly without raising blood sugar took years.

  • The receptor that macrophages depend on; blocking it shrinks tenosynovial giant cell tumour (a CSF1-driven tumour) and depletes tumour-supporting macrophages, though the latter has not yet helped patients with common cancers.

Where medicines act

Products grouped by the node they hit, most advanced first, with the cancers an approved product is linked to. Pick one above the diagram to see it light up.

AtEZH2node CXCL9/10 silenced (EZH2) in Cold tumours: immune deserts and exclusion3 products
AtFAPnode TGF-β CAFs, collagen in Cold tumours: immune deserts and exclusion2 products
AtCSF1Rnode Myeloid barrier in Cold tumours: immune deserts and exclusion2 products

How tumours escape

Records tied to this stage that describe resistance, evasion or tolerance. The resistance atlas lists the routes class by class.

Measured by

Biomarkers, tests and assays in the corpus that read this stage in a patient.

Open questions

What is not known at this stage: the atlas's own questions, the bottlenecks it bears on, and the ideas in the corpus that try to answer them.

  • What actually holds T cells at the tumour border: fibroblasts, vessels, or chemokines?
  • Why did systemic STING agonists and TGF-β traps disappoint?
Ideas 27 linked ideas

17 more ideas are linked to this stage's pathways, targets and terms; see the rankings →

Key evidence

Papers in the corpus tied to this stage's pathways, targets and terms, newest first.

4 more papers in the key-papers index →

How this page is built: the stage is one entry in a curated atlas (src/data/mechanics-atlas.ts). Players, medicines, escape routes, tests, ideas and papers are resolved from the knowledge graph at build time through the stage's pathways, targets and terms, so every item here has its own page and sources. Where a section is missing, the corpus has no record tied to the stage yet. Nothing here is medical advice; see about and methodology. Stage 6.3 of 56.