EGF and schizophrenia: Although one study reported abnormal expression of EGF and its receptor in the forebrain and serum of subjects with schizophrenia [48], another study could not find any significant change in the serum EGF levels in schizophrenia subjects compared to controls indicating the possibility that EGF may serve as a state marker, i.e., as an index of symptom-linked deficits [49].