Hypothesis: Accumulation of advanced glycation end‑products (AGEs) on long‑lived collagen is not merely stochastic damage but an evolutionarily conserved mechanism that reinforces tissue‑level tumor suppression by inducing a senescence‑associated secretory phenotype (SASP) in stromal cells, thereby limiting the proliferative capacity of pre‑malignant clones. This predicts that reducing AGE formation will increase cancer incidence in aged organisms unless compensatory immune surveillance is enhanced.

Mechanistic rationale: Non‑enzymatic glycation of collagen lysine residues creates AGE cross‑links that increase matrix stiffness without a concomitant rise in enzymatic cross‑links [2]. Elevated stiffness activates integrin‑FAK‑YAP/TAZ mechanotransduction, which in fibroblasts and mesenchymal stromal cells drives a persistent SASP characterized by IL‑6, IL‑8, and PAI‑1 secretion [1,5]. SASP factors enforce paracrine growth arrest in neighboring epithelial and progenitor cells, effectively creating a barrier to clonal expansion. In diabetic models, where AGE levels mimic those of old tissue, muscle progenitor activity is suppressed [6], consistent with a stiffness‑mediated senescence signal. If this pathway were purely deleterious, we would expect selection to favor mechanisms that prevent AGE buildup; instead, the persistence of AGE‑crosslinked collagen across long‑lived species suggests a selective advantage, likely via cancer suppression.

Testable predictions:

1. Genetic reduction of AGE formation – Overexpress glyoxalase 1 (GLO1) or treat mice with the AGE crosslink breaker alagebrium in a background prone to spontaneous tumors (e.g., p53+/-). Predicted outcome: increased tumor multiplicity and earlier onset compared with wild‑type controls, despite improved tissue compliance.
2. Mechanotransduction blockade – Administer a FAK inhibitor (defactinib) or YAP/TAZ antagonist (verteporfin) to aged wild‑type mice. Predicted outcome: phenocopy of AGE reduction – higher tumor incidence – confirming that stiffness‑dependent signaling mediates the protective effect.
3. SASP dependency – Neutralize IL‑6 or IL‑8 with antibodies in GLO1‑overexpressing, tumor‑prone mice. Predicted outcome: rescue of the tumor‑suppressive effect, restoring tumor rates to control levels despite low AGE burden.
4. Comparative species analysis – Measure collagen‑bound AGE levels and matrix stiffness in tissues of short‑lived (mouse) vs. long‑lived (human, naked mole‑rat) species, correlating with lifetime cancer risk. Predicted outcome: long‑lived species exhibit higher baseline AGE‑stiffness and stronger SASP signatures in stromal compartments.

Falsification: If AGE reduction (via GLO1 overexpression or pharmacologic crosslink breakers) fails to increase tumor incidence in any of the above models, or if tumor incidence decreases, the hypothesis that AGE‑mediated stromal senescence serves an evolved tumor‑suppressive role would be refuted, supporting the view that AGEs are purely deleterious damage.

This hypothesis reframes AGE accumulation as a programed, extracellular checkpoint that balances tissue repair with cancer prevention, suggesting that longevity interventions targeting glycation must be paired with strategies to bolster immune clearance of senescent cells or enhance alternative tumor‑suppressive pathways.