ESTRO 2025 - Abstract Book

S3905

Radiobiology - Microenvironment

ESTRO 2025

Figure 2: FN1, COL5A2 and COL1A1 mRNA expression levels are general prognostic markers for muscle-invasive bladder cancer (MIBC).

Conclusion: Radiation alters the ECM composition, mostly affecting non-structural proteins (cytokines, proteases) and glycoproteins. Those changes associated with reduced ECM fibre’s width and length, suggesting a disruption of the ECM fibre organisation. Affected ECM genes (FN1, COL5A1, COL1A1) were prognostic, acting as proof-of-concept ECM’s alterations clinical relevance. Hypoxia-modifying therapy impaired ECM genes prognostic capacity, suggesting it can be targeted. Future research should validate the findings in radiotherapy recurrent tumours and assess the impact of hypoxia on radiation-induced ECM alterations. Keywords: Bladder cancer, Hypoxia, ECM