Abstract The extracellular matrix (ECM) plays an important role in maintaining the structure and function of the kidney. During aggressive fibrotic disease of the kidney, such as chronic kidney disease (CKD), the kidney extracellular matrix is rapidly modified and degraded. Reports have shown that changes in the ECM composition and architecture can have profound influence on kidney function and recovery. The influence of ECM remodeling on disease progression and kidney function in Renal Cell Carcinoma (RCC), is still not well understood. By co-isolating primary cancer cell lines and the extracellular protein fraction from resected ccRCC tumors, we have determined that changes in collagen isoform composition are drastically altered compared to healthy normal kidney via Mass Spectrometry SWATH analysis (NvT COL1 p= 5.2x10-5; COLIII p=0.03; COLVI; COLIV p=0.004). RNA-seq analysis of TCGA data shows that altered collagen composition compared to normal correlates with patient outcomes (5 year survival COL1 HIGH=55%, LOW=72%, p=3.96e-4; COLIII HIGH=60%, LOW=73%, p=6.67e-2; COLIV HIGH=67%, LOW=56%, p=1.06e-2; COLVI HIGH=44%, LOW=71%, p=4.09e-9). Trichrome staining and IHC analysis of COLI, COLIII, and COLIV alongside cryptic-collagen epitopes XL313 and Hu177, suggests that subsets of tumor cell populations degrade surrounding collagen to drastically alter the ECM architecture. H&E scoring of regions of high XL313/Hu177 staining shows increased grade compared to low/no-staining. Isolated primary ccRCC cancer lines were analyzed for differential adherence to collagen isoforms, showing preferential binding preferences. In parallel, isolated normal kidney epithelia and renal proximal tubule epithelial cells (RPTECs) adherence preference was also investigated. Freshly dissociated tumor tissue cultured on a novel ECM cocktail coating in 3D scaffolds show changes in cell viability, growth, and purity compared to standard tissue culture conditions. In this study, we conclude that collagen composition analysis through IHC and Mass Spectrometry can be indicative of patient tumor aggressiveness. Preferential binding to collagen isoforms by tumor cells and the lack of adherence by normal kidney epithelia indicates a novel mechanism for tumor cells to promote local invasion. Additionally, we have generated a novel method by which to isolate human ccRCC cell lines using a collagen cocktail that will be useful for basic research and disease modeling. Note: This abstract was not presented at the meeting. Citation Format: Kyle H. Bond, Anna Deck, Jennifer Caron, Peter Brooks, Calvin Vary, Sunder Sims-Lucas, Leif Oxburgh. Collagen remodeling in clear cell renal cell carcinoma: Influence of composition on growth and metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1901.