EGFR and cyst: However, Argos is induced by EGFR signaling (Golembo et al., 1996), which occurs at high levels in cyst lineage cells in adult testes (Chen et al., 2013; Fairchild et al., 2016; Schulz et al., 2002), suggesting that cyst lineage cells could be a source of Argos in the testis.