EWSR1 and Familial prostate cancer: Since the original publication of YK-4-279 as an inhibitor of EWSR1-FLI1, the molecule has been shown to suppress growth of a variety of cancer cell lines not driven by EWSR1-FLI1, including prostate cancer, neuroblastoma, lymphoma, melanoma, and thyroid cancer (Huang et al., 2021; Kollareddy et al., 2017; Rahim et al., 2014; Spriano et al., 2019; Xue et al., 2021).