Dissecting CAF Heterogeneity in Glioblastoma Reveals Prognostic Subtypes and a Central Regulatory Role for Spleen Tyrosine Kinase (SYK).

Background: Cancer-associated fibroblasts (CAFs) are key components of the glioblastoma (GBM) microenvironment and contribute to tumor progression, immune evasion, and therapy resistance. However, their heterogeneity and clinical impact in GBM remain poorly defined. Methods: We performed an integrative transcriptomic analysis combining bulk and single-cell RNA sequencing (scRNA-seq) datasets to characterize CAF subtypes in GBM. Four CAF-associated transcriptional programs were defined based on canonical gene signatures: immune CAFs, myofibroblastic CAFs (myoCAFs), inflammatory CAFs (iCAFs), and antigen-presenting CAFs (apCAFs). Prognostic relevance was assessed using survival analyses, and hub genes were identified through network analysis. Results: CAF subtype-specific gene signatures were significantly associated with poor overall survival. Single-cell analysis revealed spatial heterogeneity of CAF activation, with immune and inflammatory CAF markers enriched in low-stemness tumor cells. SYK was identified as a central hub gene shared across CAF subtypes, suggesting its role in stromal signaling. Conclusions: Our study reveals CAF subtype-associated patterns with prognostic and functional relevance in GBM. Targeting CAF subpopulations and key mediators such as SYK may represent a promising therapeutic strategy in GBM.