🩸 The Discovery: Ageing Blood Mutations Fuel Cancer Evolution
In a groundbreaking revelation from the Francis Crick Institute, researchers have uncovered how mutations in ageing blood cells can dramatically influence cancer development. Published as part of ongoing work building on a landmark 2025 New England Journal of Medicine study, the findings highlight tumour-infiltrating clonal haematopoiesis (TI-CH), where mutant blood cells infiltrate solid tumours, promoting growth, spread, and resistance to treatment.
Charlie Swanton, Chief Clinician Scientist at the Crick, explains that these age-related changes in blood—known as clonal haematopoiesis of indeterminate potential (CHIP)—are not just passive markers of ageing but active players in cancer progression. Affecting 10-20% of individuals by age 70, CHIP mutations lead to the clonal expansion of blood stem cells carrying genetic alterations, often in genes like TET2.
The study leveraged data from over 400 UK lung cancer patients in the Cancer Research UK-funded TRACERx and PEACE cohorts, revealing TI-CH in about half of cases with CHIP. These infiltrated cells, primarily myeloid immune cells such as neutrophils and macrophages, trigger chronic inflammation—termed 'inflammaging'—that remodels the tumour microenvironment to favour cancer cell survival and metastasis.
What is Clonal Haematopoiesis (CHIP)? A Step-by-Step Explanation
Clonal haematopoiesis (CH) occurs when a single mutated haematopoietic stem cell (full name: haematopoietic stem and progenitor cell, HSPC) outcompetes others, dominating blood production. CHIP specifically refers to cases without progression to blood cancer, distinguished by variant allele frequencies (VAF) above 2% in genes like DNMT3A, TET2, or ASXL1.
Step 1: Accumulation of somatic mutations in HSPCs due to age, environmental exposures (e.g., smoking, pollution), or chemotherapy.
Step 2: Mutant clones expand, producing disproportionate blood cells.
Step 3: These cells circulate and infiltrate distant tissues, including tumours (TI-CH).
Step 4: In tumours, they release pro-inflammatory cytokines, enhancing cancer stemness and immune evasion.
- Prevalence: Rises exponentially with age; UK Biobank data shows ~10% at 70, up to 62% over 80.
- Risks: Cardiovascular disease (2x), haematological malignancies, and now solid tumours.
This process exemplifies how ageing biology intersects with oncology, with profound implications for the UK's ageing population where over 36% of cancers are diagnosed in those 75+.
Francis Crick Institute: Leading UK Cancer Evolution Research
The Francis Crick Institute, Europe's largest biomedical research centre in London, spearheads this work through its Cancer Evolution Laboratory. Funded by MRC, CRUK, Wellcome, and partners, it collaborates closely with UK universities including UCL, Imperial College London, and King's College London—joint graduate programmes train PhD students in genomics and immunology.
TRACERx (TRAcking Cancer Evolution through therapy (Rx)) tracks non-small cell lung cancer (NSCLC) from diagnosis to relapse, involving 14 UK hospitals. Complementing it, PEACE (Posthumous Evaluation of Advanced Cancer Environment) enables multi-region sampling at autopsy, mapping metastatic evolution.
Key Findings: TI-CH Drives Worse Prognosis Across Cancers
In TRACERx/PEACE NSCLC patients, CHIP shortened survival independently of stage. TI-CH amplified this: adjusted hazard ratio (HR) 1.80 for death/recurrence vs. no CHIP; 1.62 vs. CHIP without TI-CH. Metastatic sites frequently harboured TI-CH cells.
Validated in Memorial Sloan Kettering's 22,000+ pan-cancer dataset (expanded from 49k in NEJM), TI-CH linked to higher all-cause mortality (HR 1.17). Lung, head/neck, pancreatic cancers showed highest TI-CH rates—harder-to-treat types.
| Cancer Type | TI-CH Prevalence in CHIP Cases | Prognostic Impact |
|---|---|---|
| Lung (NSCLC) | 42% | HR 1.80 death/recurrence |
| Pan-cancer solid | 26% | HR 1.17 mortality |
| Head/Neck | High | Worse survival |
Mechanisms: TET2-Mutant Myeloid Cells Remodel Tumours
TET2 (ten-eleven translocation 2) mutations, epigenetic regulators, were strongest TI-CH predictors. TET2-deficient myeloid cells hyper-migrate to tumours, secrete IL-1β and other cytokines, fostering myeloid-rich microenvironments.
In mouse models and lung organoids (mini-tumours), co-culture with TET2-mutant macrophages accelerated growth, induced stem-like properties in cancer cells, and boosted metastasis—via chronic inflammation.
- Step-by-step: Mutant monocytes → tumour infiltration → cytokine storm → cancer stemness ↑ → evolution/resistance.
- Implication: Explains 'inflammaging' role in age-related cancers.
Swanton notes: “Mutations in blood cells combine with exposures to release inflammatory molecules, fuelling age-related diseases.”Full Crick announcement
UK Context: Cancer Burden in an Ageing Nation
UK cancer incidence rises with age: 54% cases in 50+, 36% 75+. Despite 20% mortality drop (1995-2020), ~380 daily deaths. NSCLC, 85% lung cancers, kills 35k yearly. Elderly (70+) face 10-20% CHIP prevalence per UK Biobank.
NHS implications: Routine CHIP screening? Tailored therapies for TI-CH patients. CRUK funds £100m+ evolution studies, positioning UK as leader.
Treatment Challenges and Resistance Linked to TI-CH
TI-CH myeloid cells shield tumours from immunotherapy (e.g., PD-1 inhibitors) via PD-L1 upregulation, explaining poorer responses in elderly. Organoid data shows faster evolution under therapy stress.
Real-world: TRACERx patients with TI-CH relapsed sooner post-surgery/chemo. Broader: Links CHIP to cardiovascular risks post-cancer treatment, per UK Biobank.
Future Outlook: Targeting Inflammaging for Healthier Ageing
Therapeutics: Anti-IL-1β (canakinumab), JAK inhibitors, or TET2-modulators. Preclinical: Colchicine curbs IL-1β in CHIP models. Clinical trials needed for CHIP+ cancer patients.
Prevention: Lifestyle curbs inflammaging—exercise, Mediterranean diet reduce CHIP expansion. UK trials via CRUK/NIHR could pioneer 'anti-ageing' oncology.
Swanton: “Cooling chronic inflammation might stall cancer and age-related conditions for longer, healthier lives.”
Higher Education Opportunities: Advancing CHIP Research in UK Universities
Crick's PhD programmes with UCL/KCL train ~100 students yearly in genomics. Postdocs in Swanton's lab analyse TRACERx data. CRUK funds 100+ fellowships; UK unis like Edinburgh, Manchester lead inflammaging studies.
- Skills: Single-cell sequencing, organoids, AI tumour modelling.
- Careers: Research assistant to professor roles booming amid £2bn UKRI investment.
This positions UK higher ed as global hub for precision oncology.NEJM study on TI-CH
Photo by Danie Franco on Unsplash
Stakeholder Perspectives and Actionable Insights
Oncologists: Integrate blood sequencing in elderly diagnostics. Patients: Monitor inflammation markers. Policymakers: Fund CHIP trials via NHS Genomic Medicine Service.
Case: 70yo NSCLC patient with TET2-CHIP/TI-CH relapsed 6 months post-op vs. 24+ without. Future: ctDNA monitoring for early intervention.
Balanced view: CHIP screening ethical? Benefits outweigh anxiety?
