Myxoid liposarcoma (MLS) is the second most common type of liposarcoma, and today few model systems to study the disease exists. To be able to model the disease in vitro, cell-free scaffolds from MLS patient-derived xenograft (PDX) models were generated. The MLS scaffolds were then used as a 3D growth platform for MLS cell lines to study the cancer microenvironments impact on cellular heterogeneity using RNA sequencing. Key components in the microenvironment have also been shown to influence the fraction of cellular subpopulations, such as cancer stem cells and migratory cells but also to promote aggressive features of cancers. Therefore, to better understand and characterize these scaffolds, protein analyses were performed and links between scaffold compositions and the induced gene expression profiles of the cells grown therein could be made. This model system provides a better insight to the composition of the cell-free cancer microenvironment in a rare disease, which can lead to identification of novel malignancy inducing properties in MLS.