PTPRC and synovial sarcoma: FACS selection of EpCAMhigh cells from primary SS biopsies, after removal of infiltrating leukocytes, did not rescue the self‐renewal potential of primary SS SGSCs (Supplementary Figure 3, http://onlinelibrary.wiley.com/doi/10.1002/art.40659/abstract), indicating that the sole presence of CD45+ cells in SGs of patients with primary SS is not responsible for the regenerative deficits observed.