AREG and cirrhosis of liver: Mice with loss-of-function mutations in areg show decreased cellular proliferation following partial hepatectomy.43 In samples from both cirrhotic human livers and a rat model of liver cirrhosis, amphiregulin levels are elevated.43 Together, these data suggest that a balance between the need for amphiregulin in early healing and the pathological consequences of too much amphiregulin may exist across many species and organs.