AREG and neoplasm: Among the family of HER receptor ligands, amphiregulin (AREG) and epiregulin in particular have been studied for their involvement in the responsiveness of tumours to cetuximab-containing regimens (Baker et al. 2011; Cushman et al. 2015; Jacobs et al. 2009; Jonker et al. 2014; Khambata-Ford et al. 2007; Pentheroudakis et al. 2013; Takahashi et al. 2014; Yoshida et al. 2013).