ERBB3 and neoplasm: In this regard, the finding that compensatory activation of ERBB3-driven signalling occurs rapidly in response to FGFR inhibition in multiple models of FGFR3-fusion harbouring bladder cancer, and our demonstration that dual targeting of FGFR and ERBB family receptors synergistically inhibits growth, suggests that dual blockade of FGFR and ERBB-driven signalling may represent a more effective treatment strategy for these tumours.