Neuregulin 4Neuregulin 4 also known as NRG4 is a member of the neuregulin protein family which in humans is encoded by the NRG4 gene.FunctionThe neuregulins, including NRG4, activate erb-b2 receptor tyrosine kinase 4 to initiating cell signaling through cytosolic tyrosine phosphorylation.Clinical significanceLoss of expression of NRG4 is frequently seen in advanced bladder cancer while increased NRG4 expression correlates to better survival.