EGR1 is a direct target of SS18-SSX (de Bruijn et al., 2006; Lubieniecka et al., 2008) and its transcription level is negatively correlated with SS18-SSX activity in synovial sarcoma cells (Su et al., 2010; Laporte et al., 2016). Here, SSX2 is linked to synovial sarcoma.