Cell proliferation, immune cell infiltration, and survival outcomes in sarcomas with high cancer-associated fibroblast expression.

11541 Background: Cancer-associated fibroblasts (CAFs) play an integral role in the tumor microenvironment and have been linked to tumor aggravation and promotion of metastatic potential. CAFs are often abundant in sarcomas, but their role is understudied partly because both share a similar mesenchymal origin. We aimed to investigate the relationship between CAFs and clinical characteristics in sarcomas using transcriptomics. Methods: Genomic and clinicopathologic data was acquired from The Cancer Genome Atlas Sarcoma cohort. Cases were divided into high and low CAF groups using the median CAF level. Immune cell compositions including CAFs were determined using the xCell algorithm. Institutional Review Board waiver was deemed applicable as the data is de-identified from publicly available databases. Results: A total of 258 patients including leiomyosarcoma (LMS, n=83), myxofibrosarcoma/undifferentiated pleomorphic sarcoma (MFS/UPS, n=80), dedifferentiated liposarcoma (DDLPS, n=46), and other pathologies (n=20), were analyzed. DDLPS had significantly greater CAFs than the other subtypes (p=0.0025). CAF expression varied significantly by tumor grade, with grade 3 tumors having the lowest CAF expression and grade 1 & 2 tumors having significantly higher CAF expression (p