Immunosenescence is a biological process accompanying ageing, characterized by increased susceptibility to infections, reduced vaccine efficacy, and the development of chronic low-grade inflammation. Although immunosenescence is systemic, the relative contribution and compensability of each organ in the adaptive immune axis remain debated. We consolidate current evidence supporting a thymus-centric model of immune ageing. In this model, early and progressive thymic involution, marked by thymic epithelial cell attrition, FOXN1 decline, and architectural disruption, emerges as the principal constraint on de novo naive T‑cell production and T-cell receptor (TCR) repertoire renewal. In contrast, age‑related changes in bone marrow and spleen often exhibit partial compensability through peripheral redistribution and clinical interventions, sustaining counts but not restoring de novo diversity. We evaluate mechanisms of thymic involution, inter-organ communication, and cross-species parallels, identifying shared features across animal models. Quantitative readouts, including age-associated declines in sjTRECs and TCR-β repertoire diversity, further support the thymus-centricity. Clinically, constrained thymopoiesis may undercut vaccine responsiveness and reduce the efficacy of cancer immunotherapies (chimeric antigen receptor T-cell and immune checkpoint inhibitors) in older adults. We assess genetic, pharmacological, and bioengineering strategies to preserve or restore thymic function and outline translational paths and endpoints for future trials.

The treatment of early invasive breast cancer in older patients poses unique challenges due to the distinct biological, clinical, and psychosocial complexities associated with aging. As the population of breast cancer patients aged 70 years and older continues to grow, their persistent underrepresentation in clinical trials remains a major obstacle to evidence-based treatment decision-making. To support the development of a more effective, personalized, and patient-centered approach to systemic therapy, this review outlines the biological features of breast cancer in older women, synthesizes current evidence on neoadjuvant and adjuvant systemic therapies, and discusses strategies for individualized treatment decision-making. Key recommendations include the use of hormonal therapy as the standard of care for hormone receptor positive breast cancer, neoadjuvant therapy primarily when tumor downstaging is desired, and chemotherapy or anti-human epidermal growth factor receptor 2 therapy for relatively fit older patients with high-risk subtypes. Additionally, bisphosphonates may help preserve bone health and reduce recurrence risk. Novel targeted therapies such as cyclin-dependent kinase 4 and 6 inhibitors and immune checkpoint inhibitors show promise, though further studies are needed to confirm their safety and efficacy in older populations. Comprehensive geriatric assessments are essential for identifying patient frailty and vulnerabilities, while predictive tools such as the Cancer and Aging Research Group Breast Cancer model can help assess toxicity risk. In this population, competing risks of non-cancer-related mortality may reduce the absolute benefit of systemic treatment. For patients with elevated risks of other-cause mortality, the potential survival benefit of cancer therapy may be negligible. Predictive models that account for competing mortality, such as the PORTRET tool, can facilitate personalized and shared decision-making.

Aims: The combination of CDK4/6 inhibitors and endocrine therapy (ET) is a standard first-line therapy for hormone receptor positive (HR+)/HER2- metastatic breast cancer (mBC). Preliminary data suggest that CDK4/6 inhibitors can alter the host immune function and stimulate tumor cell-directed immunity. However, clinical data are scarce, and no data exist about the impact of age and frailty on this phenomenon.

Materials and Methods: This biomarker substudy of the RibOB trial evaluated the impact of ribociclib and letrozole on circulating immune cell subsets and protein markers in older (≥ 70 years) patients with HR+/HER2- mBC. Peripheral blood mononuclear cell subtyping and analysis of plasma immune response and checkpoint markers were performed using flow cytometry at baseline and after three months of ribociclib + ET. Frailty status was assessed at baseline using G8 score.

Results: 20 patients (median age: 76 years, range: 70-87 years), 8 considered fit (G8 > 14), and 12 frail (G8 ≤ 14), were included. After three months of treatment, the immune subset composition showed significant increases in naïve B-, T-regulatory (Tregs), and CD4+ T-cells, while memory B-cells and Tregs were significantly decreased. In addition, consistent upregulation was seen in costimulatory receptors CD27 and CD28. Plasma immune checkpoint markers B7.2 (CD86) and PD-1 were significantly decreased. The immune subset profiles of fit versus frail persons showed no statistically significant difference.

Conclusion: The study shows that the combination of ribociclib and ET modulates the immune system in older patients, potentially reversing the age-related immunosenescence process by increasing naïve T-cell and B-cell populations and decreasing memory populations.

Clinical trial registration number: NCT03956654.

It is becoming increasingly clear that the tumour microenvironment (TME) adopts a changing and increasingly complex landscape as tumours evolve. Central to the TME, and alongside malignant cells, are tissue resident and recruited macrophages, other immune cells, and endothelial cells, with the latter critical for angiogenesis and tumour development. Tumour vessels provide oxygen and nutrients and are portals for immune cells. Tumour cells, immune cells and endothelial cells engage in multi-directional crosstalk that untimately influence tumour progression and treatment responses. Adding to complexity, the TME often consists of oxygenated, and oxygen deprived or hypoxic regions, with the latter significantly contributing to disease progression and treatment resistance. However, the function of immune cells and endothelial cells change with ageing, and this underexplored area likely influences the aged TME and disease outcomes in the elderly. Solid cancers such as mesothelioma with known carcinogen exposure (asbestos) take decades to reach a diagnosable size, often emerging in people aged 60 years or more. Here, we discuss the influence of ageing on the function of tumour-associated immune cells, focussing on macrophages, and their possible interactions with endothelial cells, and how this might impact the evolving mesothelioma TME in elderly people.

Growth Differentiation Factor 15 (GDF15), a member of the transforming growth factor-beta superfamily, is highly expressed in response to cellular stress, ageing, and various pathological conditions. As a key component of the senescence-associated secretory phenotype, it plays important roles in modulating inflammation, mitochondrial dysfunction, energy metabolism, and appetite. It signals through the glial-derived neurotrophic factor receptor alpha-like receptor in the brainstem to suppress appetite and modulate energy balance. Increasing evidence supports that GDF15 exhibits dual and context-dependent functions in cancer, contributing to both tumor suppression and progression through its regulation of cellular proliferation, metastasis, and interactions within the tumor microenvironment. Elevated GDF15 levels have been observed in cardiovascular diseases, metabolic disorders, neurodegenerative diseases, and numerous malignancies, making it a potential biomarker and therapeutic target for a spectrum of age-related and pathological conditions, including cancer. Emerging therapeutic strategies targeting GDF15 encompass the use of agonists for obesity and antagonists for cachexia, either alone or in combination with immunotherapy, reflecting its complex role in disease. A comprehensive understanding of its context-dependent roles may shed light on fundamental disease mechanisms, offering a foundation for the development of innovative and personalized therapeutic approaches.

Immunosenescence is a biological process accompanying ageing, characterized by increased susceptibility to infections, reduced vaccine efficacy, and the development of chronic low-grade inflammation. Although immunosenescence is systemic, the relative contribution and compensability of each organ in the adaptive immune axis remain debated. We consolidate current evidence supporting a thymus-centric model of immune ageing. In this model, early and progressive thymic involution, marked by thymic epithelial cell attrition, FOXN1 decline, and architectural disruption, emerges as the principal constraint on de novo naive T‑cell production and T-cell receptor (TCR) repertoire renewal. In contrast, age‑related changes in bone marrow and spleen often exhibit partial compensability through peripheral redistribution and clinical interventions, sustaining counts but not restoring de novo diversity. We evaluate mechanisms of thymic involution, inter-organ communication, and cross-species parallels, identifying shared features across animal models. Quantitative readouts, including age-associated declines in sjTRECs and TCR-β repertoire diversity, further support the thymus-centricity. Clinically, constrained thymopoiesis may undercut vaccine responsiveness and reduce the efficacy of cancer immunotherapies (chimeric antigen receptor T-cell and immune checkpoint inhibitors) in older adults. We assess genetic, pharmacological, and bioengineering strategies to preserve or restore thymic function and outline translational paths and endpoints for future trials.

Aims: Recurrent and uncontrolled inflammation of the colon may cause inflammatory bowel diseases (IBD), which are strongly associated with the onset of colitis-associated cancer (CAC). However, the molecular mechanisms linking inflammation, dysregulated growth, and tumorigenesis remain unclear. This study aims to determine the role of the N⁶-methyladenosine (m⁶A) reader YTH m⁶A RNA binding protein 1 (Ythdf1) in regulating colitis severity and CAC development.

Methods: Ythdf1-deficient and wild-type mice were subjected to dextran sodium sulfate (DSS)-induced colitis to evaluate disease severity, epithelial survival, goblet cell and mucus preservation, and inflammatory signaling. m⁶A-dependent regulation of Jak1 mRNA and the Il6-Jak1-Stat3 pathway activation was assessed through molecular analyses. Additionally, an azoxymethane (AOM)/DSS model was used to determine the impact of Ythdf1 loss on CAC development.

Results: Ythdf1 deficiency significantly worsened DSS-induced colitis, with increased epithelial damage, loss of goblet cells and mucus, impaired epithelial survival, and reduced Stat3 activation. Mechanistically, Ythdf1 recognized m⁶A-modified Jak1 mRNA and enhanced Jak1 protein expression, thereby maintaining the Il6-Jak1-Stat3 signaling during inflammatory stress. Despite aggravating colitis, Ythdf1 loss markedly suppressed CAC progression and reduced tumor burden.

Conclusion: Ythdf1 is a key regulator of intestinal homeostasis, maintaining the Il6-Jak1-Stat3 signaling to protect against colitis while paradoxically promoting CAC progression. These findings identify Ythdf1 as a context-dependent modulator of intestinal inflammation and tumorigenesis, highlighting its therapeutic potential in IBD and CAC.

It is becoming increasingly clear that the tumour microenvironment (TME) adopts a changing and increasingly complex landscape as tumours evolve. Central to the TME, and alongside malignant cells, are tissue resident and recruited macrophages, other immune cells, and endothelial cells, with the latter critical for angiogenesis and tumour development. Tumour vessels provide oxygen and nutrients and are portals for immune cells. Tumour cells, immune cells and endothelial cells engage in multi-directional crosstalk that untimately influence tumour progression and treatment responses. Adding to complexity, the TME often consists of oxygenated, and oxygen deprived or hypoxic regions, with the latter significantly contributing to disease progression and treatment resistance. However, the function of immune cells and endothelial cells change with ageing, and this underexplored area likely influences the aged TME and disease outcomes in the elderly. Solid cancers such as mesothelioma with known carcinogen exposure (asbestos) take decades to reach a diagnosable size, often emerging in people aged 60 years or more. Here, we discuss the influence of ageing on the function of tumour-associated immune cells, focussing on macrophages, and their possible interactions with endothelial cells, and how this might impact the evolving mesothelioma TME in elderly people.

Aims: The combination of CDK4/6 inhibitors and endocrine therapy (ET) is a standard first-line therapy for hormone receptor positive (HR+)/HER2- metastatic breast cancer (mBC). Preliminary data suggest that CDK4/6 inhibitors can alter the host immune function and stimulate tumor cell-directed immunity. However, clinical data are scarce, and no data exist about the impact of age and frailty on this phenomenon.

Materials and Methods: This biomarker substudy of the RibOB trial evaluated the impact of ribociclib and letrozole on circulating immune cell subsets and protein markers in older (≥ 70 years) patients with HR+/HER2- mBC. Peripheral blood mononuclear cell subtyping and analysis of plasma immune response and checkpoint markers were performed using flow cytometry at baseline and after three months of ribociclib + ET. Frailty status was assessed at baseline using G8 score.

Results: 20 patients (median age: 76 years, range: 70-87 years), 8 considered fit (G8 > 14), and 12 frail (G8 ≤ 14), were included. After three months of treatment, the immune subset composition showed significant increases in naïve B-, T-regulatory (Tregs), and CD4+ T-cells, while memory B-cells and Tregs were significantly decreased. In addition, consistent upregulation was seen in costimulatory receptors CD27 and CD28. Plasma immune checkpoint markers B7.2 (CD86) and PD-1 were significantly decreased. The immune subset profiles of fit versus frail persons showed no statistically significant difference.

Conclusion: The study shows that the combination of ribociclib and ET modulates the immune system in older patients, potentially reversing the age-related immunosenescence process by increasing naïve T-cell and B-cell populations and decreasing memory populations.

Clinical trial registration number: NCT03956654.

Growth Differentiation Factor 15 (GDF15), a member of the transforming growth factor-beta superfamily, is highly expressed in response to cellular stress, ageing, and various pathological conditions. As a key component of the senescence-associated secretory phenotype, it plays important roles in modulating inflammation, mitochondrial dysfunction, energy metabolism, and appetite. It signals through the glial-derived neurotrophic factor receptor alpha-like receptor in the brainstem to suppress appetite and modulate energy balance. Increasing evidence supports that GDF15 exhibits dual and context-dependent functions in cancer, contributing to both tumor suppression and progression through its regulation of cellular proliferation, metastasis, and interactions within the tumor microenvironment. Elevated GDF15 levels have been observed in cardiovascular diseases, metabolic disorders, neurodegenerative diseases, and numerous malignancies, making it a potential biomarker and therapeutic target for a spectrum of age-related and pathological conditions, including cancer. Emerging therapeutic strategies targeting GDF15 encompass the use of agonists for obesity and antagonists for cachexia, either alone or in combination with immunotherapy, reflecting its complex role in disease. A comprehensive understanding of its context-dependent roles may shed light on fundamental disease mechanisms, offering a foundation for the development of innovative and personalized therapeutic approaches.