Matrix Architecture and Integrin Branch Balance Distinguish Immune-Regulatory States in Clear Cell Renal Cell Carcinoma

Background/Objectives: Clear cell renal cell carcinoma (ccRCC) is frequently vascular and immune-infiltrated, yet durable responses to immune checkpoint blockade remain limited. This suggests that immune resistance may reflect tumor microenvironmental organization and mechanotransduction state rather than immune infiltration alone. We aimed to determine whether matrix reorganization and branch-specific integrin mechanosensing define immune-regulatory states in ccRCC, with particular attention to adenosine-associated immune resistance. Methods: We performed an integrative computational analysis of TCGA-KIRC bulk RNA-sequencing, clinical, survival, immune feature, and reverse-phase protein array data. Matrix- and mechanobiology-related programs were quantified using ssGSEA, compact z-score-based signatures, and principal component-based sensitivity analyses. Immune-regulatory programs, CAF and ECM scores, FAK/SRC activation features, and MINER-inferred transcriptional regulons were integrated using stage association, correlation, partial correlation, variance partitioning, survival, and transcriptional state analyses. Results: Matrix-centered transcriptional programs were the dominant stage-associated mechanobiology signal in ccRCC, including ECM deposition, collagen organization, matrix remodeling, fluid shear stress, and YAP/TAZ activity. A compact ECM-associated core (ECM_Stiffness_Core; a ten-gene signature whose highest-loading members include FN1, COL1A1, COL6A1, and LOX) captured a matrix reorganization program, indicating remodeling of ECM composition and architecture rather than uniform increases in tumor stiffness, pressure, or bulk mechanical load. Matrix remodeling was associated with CAF abundance, TGFβ signaling, CD276/B7-H3, CSF1-related myeloid biology, ENTPD1/CD39, and PRDM1, whereas associations with cytotoxic immune cells were weaker. Integrin mechanosensing separated into opposing branches: ITGA5/ILK/SRC-associated features aligned with higher-risk biology and adenosine-linked immune regulation, whereas PTK2/FAK–RHOA–ROCK components showed lower-risk directions. RPPA analyses supported SRC–FAK imbalance as an adverse signaling pattern. MINER analyses further separated matrix-associated immune-suppressive regulons from canonical integrin/focal adhesion states. Conclusions: Matrix reorganization and integrin branch imbalance appear to shift ccRCC toward distinct immune-regulatory states. We propose a conceptual model that matrix architecture may act as a directional suppressive amplifier, whereas the relative balance between ITGA5/ILK/SRC-associated signaling and canonical PTK2/FAK–RHOA–ROCK mechanosensing functions as an integrin branch rheostat. This framework identifies matrix remodeling, CD276/B7-H3, CSF1-related myeloid biology, adenosine signaling, and SRC–FAK imbalance as candidate biological axes for future investigation, including their potential relevance to combination strategies beyond PD-1/PD-L1 blockade. Future experimental, spatial, and treatment response studies may further clarify the mechanistic basis of these associations and evaluate their potential therapeutic relevance.